refactor: make util an object library

Instead of simply including the utility files directly, make them a
cmake object library for easy reusability between other projects within
libgit2.

Now the top-level `src` is responsible for platform selection, while the
next-level `libgit2` and `util` configurations are responsible for
identifying what objects they include.

127 files changed, 584 insertions, 377 deletions

diff --git a/cmake/SelectHashes.cmake b/cmake/SelectHashes.cmake
index bedd8c4e3..575ae8f8d 100644
--- a/cmake/SelectHashes.cmake
+++ b/cmake/SelectHashes.cmake
@@ -21,9 +21,6 @@ endif()
 
 if(USE_SHA1 STREQUAL "CollisionDetection")
 	set(GIT_SHA1_COLLISIONDETECT 1)
-	add_definitions(-DSHA1DC_NO_STANDARD_INCLUDES=1)
-	add_definitions(-DSHA1DC_CUSTOM_INCLUDE_SHA1_C=\"common.h\")
-	add_definitions(-DSHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C=\"common.h\")
 elseif(USE_SHA1 STREQUAL "OpenSSL")
 	# OPENSSL_FOUND should already be set, we're checking USE_HTTPS
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f6924eff5..bbb724057 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,4 +1,182 @@
+# The main libgit2 source tree: this CMakeLists.txt identifies platform
+# support and includes the subprojects that make up core libgit2 support.
+
+#
+# Optional build configuration settings
+#
+
+if(DEPRECATE_HARD)
+        add_definitions(-DGIT_DEPRECATE_HARD)
+endif()
+
+if(USE_LEAK_CHECKER STREQUAL "valgrind")
+	add_definitions(-DVALGRIND)
+endif()
+
+#
+# Optional debugging functionality
+#
+
+if(DEBUG_POOL)
+	set(GIT_DEBUG_POOL 1)
+endif()
+add_feature_info(debugpool GIT_DEBUG_POOL "debug pool allocator")
+
+if(DEBUG_STRICT_ALLOC)
+	set(GIT_DEBUG_STRICT_ALLOC 1)
+endif()
+add_feature_info(debugalloc GIT_DEBUG_STRICT_ALLOC "debug strict allocators")
+
+if(DEBUG_STRICT_OPEN)
+	set(GIT_DEBUG_STRICT_OPEN 1)
+endif()
+add_feature_info(debugopen GIT_DEBUG_STRICT_OPEN "path validation in open")
+
+#
+# Optional feature enablement
+#
+
+include(SelectGSSAPI)
+include(SelectHTTPSBackend)
+include(SelectHashes)
+include(SelectHTTPParser)
+include(SelectRegex)
+include(SelectSSH)
+include(SelectWinHTTP)
+include(SelectZlib)
+
+#
+# Platform support
+#
+
+# futimes/futimens
+
+if(HAVE_FUTIMENS)
+	set(GIT_USE_FUTIMENS 1)
+endif ()
+add_feature_info(futimens GIT_USE_FUTIMENS "futimens support")
+
+# qsort
+
+check_prototype_definition(qsort_r
+	"void qsort_r(void *base, size_t nmemb, size_t size, void *thunk, int (*compar)(void *, const void *, const void *))"
+	"" "stdlib.h" GIT_QSORT_R_BSD)
+
+check_prototype_definition(qsort_r
+	"void qsort_r(void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *, void *), void *arg)"
+	"" "stdlib.h" GIT_QSORT_R_GNU)
+
+check_function_exists(qsort_s GIT_QSORT_S)
+
+# determine architecture of the machine
+
+if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+	set(GIT_ARCH_64 1)
+elseif(CMAKE_SIZEOF_VOID_P EQUAL 4)
+	set(GIT_ARCH_32 1)
+elseif(CMAKE_SIZEOF_VOID_P)
+	message(FATAL_ERROR "Unsupported architecture (pointer size is ${CMAKE_SIZEOF_VOID_P} bytes)")
+else()
+	message(FATAL_ERROR "Unsupported architecture (CMAKE_SIZEOF_VOID_P is unset)")
+endif()
+
+# nanosecond mtime/ctime support
+
+if(USE_NSEC)
+	set(GIT_USE_NSEC 1)
+endif()
+
+# high-resolution stat support
+
+if(HAVE_STRUCT_STAT_ST_MTIM)
+	set(GIT_USE_STAT_MTIM 1)
+elseif(HAVE_STRUCT_STAT_ST_MTIMESPEC)
+	set(GIT_USE_STAT_MTIMESPEC 1)
+elseif(HAVE_STRUCT_STAT_ST_MTIME_NSEC)
+	set(GIT_USE_STAT_MTIME_NSEC 1)
+endif()
+
+# realtime support
+
+check_library_exists(rt clock_gettime "time.h" NEED_LIBRT)
+if(NEED_LIBRT)
+	list(APPEND LIBGIT2_SYSTEM_LIBS rt)
+	list(APPEND LIBGIT2_PC_LIBS "-lrt")
+endif()
+
+# platform libraries
+
+if(WIN32)
+	list(APPEND LIBGIT2_SYSTEM_LIBS ws2_32)
+endif()
+
+if(CMAKE_SYSTEM_NAME MATCHES "(Solaris|SunOS)")
+	list(APPEND LIBGIT2_SYSTEM_LIBS socket nsl)
+	list(APPEND LIBGIT2_PC_LIBS "-lsocket" "-lnsl")
+endif()
+
+if(CMAKE_SYSTEM_NAME MATCHES "Haiku")
+	list(APPEND LIBGIT2_SYSTEM_LIBS network)
+	list(APPEND LIBGIT2_PC_LIBS "-lnetwork")
+endif()
+
+if(AMIGA)
+	add_definitions(-DNO_ADDRINFO -DNO_READDIR_R -DNO_MMAP)
+endif()
+
+# threads
+
+if(USE_THREADS)
+	if(NOT WIN32)
+		find_package(Threads REQUIRED)
+		list(APPEND LIBGIT2_SYSTEM_LIBS ${CMAKE_THREAD_LIBS_INIT})
+		list(APPEND LIBGIT2_PC_LIBS ${CMAKE_THREAD_LIBS_INIT})
+	endif()
+
+	set(GIT_THREADS 1)
+endif()
+add_feature_info(threadsafe USE_THREADS "threadsafe support")
+
+#
+# Optional bundled features
+#
+
+# ntlmclient
+if(USE_NTLMCLIENT)
+	set(GIT_NTLM 1)
+	add_subdirectory("${libgit2_SOURCE_DIR}/deps/ntlmclient" "${libgit2_BINARY_DIR}/deps/ntlmclient")
+	list(APPEND LIBGIT2_DEPENDENCY_INCLUDES "${libgit2_SOURCE_DIR}/deps/ntlmclient")
+	list(APPEND LIBGIT2_DEPENDENCY_OBJECTS "$<TARGET_OBJECTS:ntlmclient>")
+endif()
+add_feature_info(ntlmclient GIT_NTLM "NTLM authentication support for Unix")
+
+#
+# Optional external dependencies
+
+# iconv
+if(USE_ICONV)
+	find_package(Iconv)
+endif()
+if(ICONV_FOUND)
+	set(GIT_USE_ICONV 1)
+	list(APPEND LIBGIT2_SYSTEM_INCLUDES ${ICONV_INCLUDE_DIR})
+	list(APPEND LIBGIT2_SYSTEM_LIBS ${ICONV_LIBRARIES})
+	list(APPEND LIBGIT2_PC_LIBS ${ICONV_LIBRARIES})
+endif()
+add_feature_info(iconv GIT_USE_ICONV "iconv encoding conversion support")
+
+#
+# Configure support
+#
+
+configure_file(features.h.in git2/sys/features.h)
+
+#
+# Include child projects
+#
+
 add_subdirectory(libgit2)
+add_subdirectory(util)
 
 # re-export these to the root so that peer projects (tests, fuzzers,
 # examples) can use them
diff --git a/src/README.md b/src/README.md
new file mode 100644
index 000000000..12e0d0e43
--- /dev/null
+++ b/src/README.md
@@ -0,0 +1,10 @@
+# libgit2 sources
+
+This is the source that makes up the core of libgit2 and its related
+projects.
+
+* `libgit2`  
+  This is the libgit2 project, a cross-platform, linkable library
+  implementation of Git that you can use in your application.
+* `util`  
+  A shared utility library for these projects.
diff --git a/src/libgit2/features.h.in b/src/features.h.in
index f920135da..f920135da 100644
--- a/src/libgit2/features.h.in
+++ b/src/features.h.in
diff --git a/src/libgit2/CMakeLists.txt b/src/libgit2/CMakeLists.txt
index e6cdddd49..3dac83d7a 100644
--- a/src/libgit2/CMakeLists.txt
+++ b/src/libgit2/CMakeLists.txt
@@ -2,94 +2,99 @@ add_library(git2internal OBJECT)
 set_target_properties(git2internal PROPERTIES C_STANDARD 90)
 set_target_properties(git2internal PROPERTIES C_EXTENSIONS OFF)
 
-
-if(DEPRECATE_HARD)
-        add_definitions(-DGIT_DEPRECATE_HARD)
-endif()
-
-if(DEBUG_POOL)
-	set(GIT_DEBUG_POOL 1)
-endif()
-add_feature_info(debugpool GIT_DEBUG_POOL "debug pool allocator")
-
-if(DEBUG_STRICT_ALLOC)
-	set(GIT_DEBUG_STRICT_ALLOC 1)
-endif()
-add_feature_info(debugalloc GIT_DEBUG_STRICT_ALLOC "debug strict allocators")
-
-if(DEBUG_STRICT_OPEN)
-	set(GIT_DEBUG_STRICT_OPEN 1)
-endif()
-add_feature_info(debugopen GIT_DEBUG_STRICT_OPEN "path validation in open")
-
-
 include(PkgBuildConfig)
-include(SanitizeBool)
-
-# This variable will contain the libraries we need to put into
-# libgit2.pc's Requires.private. That is, what we're linking to or
-# what someone who's statically linking us needs to link to.
-set(LIBGIT2_PC_REQUIRES "")
-# This will be set later if we use the system's http-parser library or
-# use iconv (OSX) and will be written to the Libs.private field in the
-# pc file.
-set(LIBGIT2_PC_LIBS "")
 
 set(LIBGIT2_INCLUDES
-	"${CMAKE_CURRENT_BINARY_DIR}"
+	"${PROJECT_BINARY_DIR}/src"
 	"${PROJECT_SOURCE_DIR}/src/libgit2"
+	"${PROJECT_SOURCE_DIR}/src/util"
 	"${PROJECT_SOURCE_DIR}/include")
 
-if(HAVE_FUTIMENS)
-	set(GIT_USE_FUTIMENS 1)
-endif ()
-add_feature_info(futimens GIT_USE_FUTIMENS "futimens support")
+if(WIN32 AND EMBED_SSH_PATH)
+	file(GLOB SRC_SSH "${EMBED_SSH_PATH}/src/*.c")
+	list(SORT SRC_SSH)
+	target_sources(git2internal PRIVATE ${SRC_SSH})
 
-check_prototype_definition(qsort_r
-	"void qsort_r(void *base, size_t nmemb, size_t size, void *thunk, int (*compar)(void *, const void *, const void *))"
-	"" "stdlib.h" GIT_QSORT_R_BSD)
+	list(APPEND LIBGIT2_SYSTEM_INCLUDES "${EMBED_SSH_PATH}/include")
+	file(WRITE "${EMBED_SSH_PATH}/src/libssh2_config.h" "#define HAVE_WINCNG\n#define LIBSSH2_WINCNG\n#include \"../win32/libssh2_config.h\"")
+	set(GIT_SSH 1)
+endif()
 
-check_prototype_definition(qsort_r
-	"void qsort_r(void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *, void *), void *arg)"
-	"" "stdlib.h" GIT_QSORT_R_GNU)
+<<<<<<< HEAD
+include(SelectHTTPSBackend)
+include(SelectHashes)
+include(SelectHTTPParser)
+include(SelectRegex)
+include(SelectSSH)
+include(SelectWinHTTP)
+include(SelectZlib)
 
-check_function_exists(qsort_s GIT_QSORT_S)
 
-# Find required dependencies
+if(USE_SHA1 STREQUAL "CollisionDetection")
+	file(GLOB SRC_SHA1 hash/sha1/collisiondetect.* hash/sha1/sha1dc/*)
+elseif(USE_SHA1 STREQUAL "OpenSSL")
+	file(GLOB SRC_SHA1 hash/sha1/openssl.*)
+elseif(USE_SHA1 STREQUAL "CommonCrypto")
+	file(GLOB SRC_SHA1 hash/sha1/common_crypto.*)
+elseif(USE_SHA1 STREQUAL "mbedTLS")
+	file(GLOB SRC_SHA1 hash/sha1/mbedtls.*)
+elseif(USE_SHA1 STREQUAL "Win32")
+	file(GLOB SRC_SHA1 hash/sha1/win32.*)
+elseif(USE_SHA1 STREQUAL "Generic")
+	file(GLOB SRC_SHA1 hash/sha1/generic.*)
+endif()
+list(APPEND SRC_SHA1 "hash/sha1.h")
+target_sources(git2internal PRIVATE ${SRC_SHA1})
 
-if(WIN32)
-	list(APPEND LIBGIT2_SYSTEM_LIBS ws2_32)
-elseif(CMAKE_SYSTEM_NAME MATCHES "(Solaris|SunOS)")
-	list(APPEND LIBGIT2_SYSTEM_LIBS socket nsl)
-	list(APPEND LIBGIT2_PC_LIBS "-lsocket" "-lnsl")
-elseif(CMAKE_SYSTEM_NAME MATCHES "Haiku")
-	list(APPEND LIBGIT2_SYSTEM_LIBS network)
-	list(APPEND LIBGIT2_PC_LIBS "-lnetwork")
+# Optional external dependency: ntlmclient
+if(USE_NTLMCLIENT)
+	set(GIT_NTLM 1)
+	add_subdirectory("${PROJECT_SOURCE_DIR}/deps/ntlmclient" "${PROJECT_BINARY_DIR}/deps/ntlmclient")
+	list(APPEND LIBGIT2_DEPENDENCY_INCLUDES "${PROJECT_SOURCE_DIR}/deps/ntlmclient")
+	list(APPEND LIBGIT2_DEPENDENCY_OBJECTS "$<TARGET_OBJECTS:ntlmclient>")
 endif()
+add_feature_info(ntlmclient GIT_NTLM "NTLM authentication support for Unix")
 
-check_library_exists(rt clock_gettime "time.h" NEED_LIBRT)
-if(NEED_LIBRT)
-	list(APPEND LIBGIT2_SYSTEM_LIBS rt)
-	list(APPEND LIBGIT2_PC_LIBS "-lrt")
+# Optional external dependency: GSSAPI
+
+include(SelectGSSAPI)
+
+# Optional external dependency: iconv
+if(USE_ICONV)
+	find_package(Iconv)
 endif()
+if(ICONV_FOUND)
+	set(GIT_USE_ICONV 1)
+	list(APPEND LIBGIT2_SYSTEM_INCLUDES ${ICONV_INCLUDE_DIR})
+	list(APPEND LIBGIT2_SYSTEM_LIBS ${ICONV_LIBRARIES})
+	list(APPEND LIBGIT2_PC_LIBS ${ICONV_LIBRARIES})
+endif()
+add_feature_info(iconv GIT_USE_ICONV "iconv encoding conversion support")
+
 
 if(USE_THREADS)
-	list(APPEND LIBGIT2_SYSTEM_LIBS ${CMAKE_THREAD_LIBS_INIT})
-	list(APPEND LIBGIT2_PC_LIBS ${CMAKE_THREAD_LIBS_INIT})
-endif()
-add_feature_info(threadsafe USE_THREADS "threadsafe support")
+	if(NOT WIN32)
+		find_package(Threads REQUIRED)
+	endif()
 
+	set(GIT_THREADS 1)
+endif()
 
-if(WIN32 AND EMBED_SSH_PATH)
-	file(GLOB SRC_SSH "${EMBED_SSH_PATH}/src/*.c")
-	list(SORT SRC_SSH)
-	target_sources(git2internal PRIVATE ${SRC_SSH})
+if(USE_NSEC)
+	set(GIT_USE_NSEC 1)
+endif()
 
-	list(APPEND LIBGIT2_SYSTEM_INCLUDES "${EMBED_SSH_PATH}/include")
-	file(WRITE "${EMBED_SSH_PATH}/src/libssh2_config.h" "#define HAVE_WINCNG\n#define LIBSSH2_WINCNG\n#include \"../win32/libssh2_config.h\"")
-	set(GIT_SSH 1)
+if(HAVE_STRUCT_STAT_ST_MTIM)
+	set(GIT_USE_STAT_MTIM 1)
+elseif(HAVE_STRUCT_STAT_ST_MTIMESPEC)
+	set(GIT_USE_STAT_MTIMESPEC 1)
+elseif(HAVE_STRUCT_STAT_ST_MTIME_NSEC)
+	set(GIT_USE_STAT_MTIME_NSEC 1)
 endif()
 
+target_compile_definitions(git2internal PRIVATE _FILE_OFFSET_BITS=64)
+
+||||||| parent of a930dafb4 (refactor: make util an object library)
 include(SelectHTTPSBackend)
 include(SelectHashes)
 include(SelectHTTPParser)
@@ -163,6 +168,8 @@ endif()
 
 target_compile_definitions(git2internal PRIVATE _FILE_OFFSET_BITS=64)
 
+=======
+>>>>>>> a930dafb4 (refactor: make util an object library)
 # Collect sourcefiles
 file(GLOB SRC_H
 	"${PROJECT_SOURCE_DIR}/include/git2.h"
@@ -171,33 +178,18 @@ file(GLOB SRC_H
 list(SORT SRC_H)
 target_sources(git2internal PRIVATE ${SRC_H})
 
-# On Windows use specific platform sources
-if(WIN32 AND NOT CYGWIN)
-	set(WIN_RC "win32/git2.rc")
-
-	file(GLOB SRC_OS win32/*.c win32/*.h)
-	list(SORT SRC_OS)
-	target_sources(git2internal PRIVATE ${SRC_OS})
-elseif(AMIGA)
-	target_compile_definitions(git2internal PRIVATE NO_ADDRINFO NO_READDIR_R NO_MMAP)
-else()
-	file(GLOB SRC_OS unix/*.c unix/*.h)
-	list(SORT SRC_OS)
-	target_sources(git2internal PRIVATE ${SRC_OS})
-endif()
-
-if(USE_LEAK_CHECKER STREQUAL "valgrind")
-	target_compile_definitions(git2internal PRIVATE VALGRIND)
-endif()
-
 file(GLOB SRC_GIT2 *.c *.h
-	allocators/*.c allocators/*.h
 	streams/*.c streams/*.h
 	transports/*.c transports/*.h
 	xdiff/*.c xdiff/*.h)
 list(SORT SRC_GIT2)
 target_sources(git2internal PRIVATE ${SRC_GIT2})
 
+if(WIN32 AND NOT CYGWIN)
+	# Add resource information on Windows
+	set(SRC_RC "git2.rc")
+endif()
+
 if(APPLE)
 	# The old Secure Transport API has been deprecated in macOS 10.15.
 	set_source_files_properties(streams/stransport.c PROPERTIES COMPILE_FLAGS -Wno-deprecated)
@@ -220,21 +212,8 @@ else()
 	set_source_files_properties(xdiff/xpatience.c PROPERTIES COMPILE_FLAGS "-Wno-sign-compare")
  endif()
 
-# Determine architecture of the machine
-if(CMAKE_SIZEOF_VOID_P EQUAL 8)
-	set(GIT_ARCH_64 1)
-elseif(CMAKE_SIZEOF_VOID_P EQUAL 4)
-	set(GIT_ARCH_32 1)
-elseif(CMAKE_SIZEOF_VOID_P)
-	message(FATAL_ERROR "Unsupported architecture (pointer size is ${CMAKE_SIZEOF_VOID_P} bytes)")
-else()
-	message(FATAL_ERROR "Unsupported architecture (CMAKE_SIZEOF_VOID_P is unset)")
-endif()
-
-configure_file(features.h.in git2/sys/features.h)
-
 ide_split_sources(git2internal)
-list(APPEND LIBGIT2_OBJECTS $<TARGET_OBJECTS:git2internal> ${LIBGIT2_DEPENDENCY_OBJECTS})
+list(APPEND LIBGIT2_OBJECTS $<TARGET_OBJECTS:util> $<TARGET_OBJECTS:git2internal> ${LIBGIT2_DEPENDENCY_OBJECTS})
 
 target_include_directories(git2internal PRIVATE ${LIBGIT2_INCLUDES} ${LIBGIT2_DEPENDENCY_INCLUDES} PUBLIC ${PROJECT_SOURCE_DIR}/include)
 target_include_directories(git2internal SYSTEM PRIVATE ${LIBGIT2_SYSTEM_INCLUDES})
@@ -254,7 +233,7 @@ if(XCODE_VERSION)
 endif()
 
 # Compile and link libgit2
-add_library(git2 ${WIN_RC} ${LIBGIT2_OBJECTS})
+add_library(git2 ${SRC_RC} ${LIBGIT2_OBJECTS})
 target_link_libraries(git2 ${LIBGIT2_SYSTEM_LIBS})
 
 set_target_properties(git2 PROPERTIES C_STANDARD 90)
diff --git a/src/libgit2/blob.c b/src/libgit2/blob.c
index 19ce8b3b5..b1680d3a8 100644
--- a/src/libgit2/blob.c
+++ b/src/libgit2/blob.c
@@ -101,7 +101,7 @@ static int write_file_stream(
 	git_oid *id, git_odb *odb, const char *path, git_object_size_t file_size)
 {
 	int fd, error;
-	char buffer[FILEIO_BUFSIZE];
+	char buffer[GIT_BUFSIZE_FILEIO];
 	git_odb_stream *stream = NULL;
 	ssize_t read_len = -1;
 	git_object_size_t written = 0;
diff --git a/src/libgit2/common.h b/src/libgit2/common.h
index 549bddb59..bb9ec5ac1 100644
--- a/src/libgit2/common.h
+++ b/src/libgit2/common.h
@@ -7,136 +7,31 @@
 #ifndef INCLUDE_common_h__
 #define INCLUDE_common_h__
 
-#ifndef LIBGIT2_NO_FEATURES_H
-# include "git2/sys/features.h"
-#endif
-
-#include "git2/common.h"
-#include "cc-compat.h"
-
-/** Declare a function as always inlined. */
-#if defined(_MSC_VER)
-# define GIT_INLINE(type) static __inline type
-#elif defined(__GNUC__)
-# define GIT_INLINE(type) static __inline__ type
-#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L)
-# define GIT_INLINE(type) static inline type
-#else
-# define GIT_INLINE(type) static type
-#endif
-
-/** Support for gcc/clang __has_builtin intrinsic */
-#ifndef __has_builtin
-# define __has_builtin(x) 0
-#endif
-
-/**
- * Declare that a function's return value must be used.
- *
- * Used mostly to guard against potential silent bugs at runtime. This is
- * recommended to be added to functions that:
- *
- * - Allocate / reallocate memory. This prevents memory leaks or errors where
- *   buffers are expected to have grown to a certain size, but could not be
- *   resized.
- * - Acquire locks. When a lock cannot be acquired, that will almost certainly
- *   cause a data race / undefined behavior.
- */
-#if defined(__GNUC__)
-# define GIT_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
-#else
-# define GIT_WARN_UNUSED_RESULT
-#endif
-
-#include <assert.h>
-#include <errno.h>
-#include <limits.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-
-#include <sys/types.h>
-#include <sys/stat.h>
-
-#ifdef GIT_WIN32
-
-# include <io.h>
-# include <direct.h>
-# include <winsock2.h>
-# include <windows.h>
-# include <ws2tcpip.h>
-# include "win32/msvc-compat.h"
-# include "win32/mingw-compat.h"
-# include "win32/w32_common.h"
-# include "win32/win32-compat.h"
-# include "win32/error.h"
-# include "win32/version.h"
-# ifdef GIT_THREADS
-#	include "win32/thread.h"
-# endif
-
-#else
-
-# include <unistd.h>
-# include <strings.h>
-# ifdef GIT_THREADS
-#	include <pthread.h>
-#	include <sched.h>
-# endif
-
-#define GIT_LIBGIT2_CALL
-#define GIT_SYSTEM_CALL
-
-#ifdef GIT_USE_STAT_ATIMESPEC
-# define st_atim st_atimespec
-# define st_ctim st_ctimespec
-# define st_mtim st_mtimespec
-#endif
-
-# include <arpa/inet.h>
-
-#endif
-
-#include "git2/types.h"
-#include "git2/errors.h"
+#include "git2_util.h"
 #include "errors.h"
-#include "thread.h"
-#include "integer.h"
-#include "assert_safe.h"
-#include "utf8.h"
 
 /*
- * Include the declarations for deprecated functions; this ensures
- * that they're decorated with the proper extern/visibility attributes.
- */
+* Include the declarations for deprecated functions; this ensures
+* that they're decorated with the proper extern/visibility attributes.
+*/
 #include "git2/deprecated.h"
 
 #include "posix.h"
 
-#define DEFAULT_BUFSIZE 65536
-#define FILEIO_BUFSIZE DEFAULT_BUFSIZE
-#define FILTERIO_BUFSIZE DEFAULT_BUFSIZE
-#define NETIO_BUFSIZE DEFAULT_BUFSIZE
-
-/**
- * Check a pointer allocation result, returning -1 if it failed.
- */
-#define GIT_ERROR_CHECK_ALLOC(ptr) do { \
-	if ((ptr) == NULL) { return -1; } \
-	} while(0)
-
 /**
- * Check a string buffer allocation result, returning -1 if it failed.
+ * Initialize a structure with a version.
  */
-#define GIT_ERROR_CHECK_ALLOC_STR(buf) do { \
-	if ((void *)(buf) == NULL || git_str_oom(buf)) { return -1; } \
-	} while(0)
+GIT_INLINE(void) git__init_structure(void *structure, size_t len, unsigned int version)
+{
+	memset(structure, 0, len);
+	*((int*)structure) = version;
+}
+#define GIT_INIT_STRUCTURE(S,V) git__init_structure(S, sizeof(*S), V)
 
-/**
- * Check a return value and propagate result if non-zero.
- */
-#define GIT_ERROR_CHECK_ERROR(code) \
-	do { int _err = (code); if (_err) return _err; } while (0)
+#define GIT_INIT_STRUCTURE_FROM_TEMPLATE(PTR,VERSION,TYPE,TPL) do { \
+	TYPE _tmpl = TPL; \
+	GIT_ERROR_CHECK_VERSION(&(VERSION), _tmpl.version, #TYPE);      \
+	memcpy((PTR), &_tmpl, sizeof(_tmpl)); } while (0)
 
 /**
  * Check a versioned structure for validity
@@ -157,58 +52,4 @@ GIT_INLINE(int) git_error__check_version(const void *structure, unsigned int exp
 }
 #define GIT_ERROR_CHECK_VERSION(S,V,N) if (git_error__check_version(S,V,N) < 0) return -1
 
-/**
- * Initialize a structure with a version.
- */
-GIT_INLINE(void) git__init_structure(void *structure, size_t len, unsigned int version)
-{
-	memset(structure, 0, len);
-	*((int*)structure) = version;
-}
-#define GIT_INIT_STRUCTURE(S,V) git__init_structure(S, sizeof(*S), V)
-
-#define GIT_INIT_STRUCTURE_FROM_TEMPLATE(PTR,VERSION,TYPE,TPL) do { \
-	TYPE _tmpl = TPL; \
-	GIT_ERROR_CHECK_VERSION(&(VERSION), _tmpl.version, #TYPE);	\
-	memcpy((PTR), &_tmpl, sizeof(_tmpl)); } while (0)
-
-
-/** Check for additive overflow, setting an error if would occur. */
-#define GIT_ADD_SIZET_OVERFLOW(out, one, two) \
-	(git__add_sizet_overflow(out, one, two) ? (git_error_set_oom(), 1) : 0)
-
-/** Check for additive overflow, setting an error if would occur. */
-#define GIT_MULTIPLY_SIZET_OVERFLOW(out, nelem, elsize) \
-	(git__multiply_sizet_overflow(out, nelem, elsize) ? (git_error_set_oom(), 1) : 0)
-
-/** Check for additive overflow, failing if it would occur. */
-#define GIT_ERROR_CHECK_ALLOC_ADD(out, one, two) \
-	if (GIT_ADD_SIZET_OVERFLOW(out, one, two)) { return -1; }
-
-#define GIT_ERROR_CHECK_ALLOC_ADD3(out, one, two, three) \
-	if (GIT_ADD_SIZET_OVERFLOW(out, one, two) || \
-		GIT_ADD_SIZET_OVERFLOW(out, *(out), three)) { return -1; }
-
-#define GIT_ERROR_CHECK_ALLOC_ADD4(out, one, two, three, four) \
-	if (GIT_ADD_SIZET_OVERFLOW(out, one, two) || \
-		GIT_ADD_SIZET_OVERFLOW(out, *(out), three) || \
-		GIT_ADD_SIZET_OVERFLOW(out, *(out), four)) { return -1; }
-
-#define GIT_ERROR_CHECK_ALLOC_ADD5(out, one, two, three, four, five) \
-	if (GIT_ADD_SIZET_OVERFLOW(out, one, two) || \
-		GIT_ADD_SIZET_OVERFLOW(out, *(out), three) || \
-		GIT_ADD_SIZET_OVERFLOW(out, *(out), four) || \
-		GIT_ADD_SIZET_OVERFLOW(out, *(out), five)) { return -1; }
-
-/** Check for multiplicative overflow, failing if it would occur. */
-#define GIT_ERROR_CHECK_ALLOC_MULTIPLY(out, nelem, elsize) \
-	if (GIT_MULTIPLY_SIZET_OVERFLOW(out, nelem, elsize)) { return -1; }
-
-/* NOTE: other git_error functions are in the public errors.h header file */
-
-/* Forward declare git_str */
-typedef struct git_str git_str;
-
-#include "util.h"
-
 #endif
diff --git a/src/libgit2/diff_xdiff.c b/src/libgit2/diff_xdiff.c
index 3f6eccac1..5f56c5209 100644
--- a/src/libgit2/diff_xdiff.c
+++ b/src/libgit2/diff_xdiff.c
@@ -11,6 +11,7 @@
 #include "diff.h"
 #include "diff_driver.h"
 #include "patch_generate.h"
+#include "utf8.h"
 
 static int git_xdiff_scan_int(const char **str, int *value)
 {
diff --git a/src/libgit2/filter.c b/src/libgit2/filter.c
index 2712e8c60..20b215729 100644
--- a/src/libgit2/filter.c
+++ b/src/libgit2/filter.c
@@ -1085,7 +1085,7 @@ int git_filter_list_stream_file(
 	const char *path,
 	git_writestream *target)
 {
-	char buf[FILTERIO_BUFSIZE];
+	char buf[GIT_BUFSIZE_FILTERIO];
 	git_str abspath = GIT_STR_INIT;
 	const char *base = repo ? git_repository_workdir(repo) : NULL;
 	git_vector filter_streams = GIT_VECTOR_INIT;
diff --git a/src/libgit2/win32/git2.rc b/src/libgit2/git2.rc
index 3f97239da..d273afd70 100644
--- a/src/libgit2/win32/git2.rc
+++ b/src/libgit2/git2.rc
@@ -1,5 +1,5 @@
 #include <winver.h>
-#include "../../../include/git2/version.h"
+#include "../../include/git2/version.h"
 
 #ifndef LIBGIT2_FILENAME
 # ifdef __GNUC__
diff --git a/src/libgit2/netops.c b/src/libgit2/netops.c
index 0a27365b8..00640c600 100644
--- a/src/libgit2/netops.c
+++ b/src/libgit2/netops.c
@@ -12,7 +12,6 @@
 
 #include "posix.h"
 #include "str.h"
-#include "http_parser.h"
 #include "runtime.h"
 
 int gitno_recv(gitno_buffer *buf)
diff --git a/src/libgit2/odb.c b/src/libgit2/odb.c
index 6d714ba54..7b98c72ee 100644
--- a/src/libgit2/odb.c
+++ b/src/libgit2/odb.c
@@ -198,7 +198,7 @@ void git_odb_object_free(git_odb_object *object)
 int git_odb__hashfd(git_oid *out, git_file fd, size_t size, git_object_t type)
 {
 	size_t hdr_len;
-	char hdr[64], buffer[FILEIO_BUFSIZE];
+	char hdr[64], buffer[GIT_BUFSIZE_FILEIO];
 	git_hash_ctx ctx;
 	ssize_t read_len = 0;
 	int error = 0;
diff --git a/src/libgit2/path.c b/src/libgit2/path.c
index 05a3dc2cf..a19340efe 100644
--- a/src/libgit2/path.c
+++ b/src/libgit2/path.c
@@ -9,6 +9,7 @@
 
 #include "repository.h"
 #include "fs_path.h"
+#include "utf8.h"
 
 typedef struct {
 	git_repository *repo;
diff --git a/src/libgit2/util/platform.h.in b/src/libgit2/util/platform.h.in
deleted file mode 100644
index e511fe331..000000000
--- a/src/libgit2/util/platform.h.in
+++ /dev/null
@@ -1,34 +0,0 @@
-#ifndef INCLUDE_platform_h__
-#define INCLUDE_platform_h__
-
-#cmakedefine GIT_DEBUG_POOL 1
-#cmakedefine GIT_DEBUG_STRICT_ALLOC 1
-#cmakedefine GIT_DEBUG_STRICT_OPEN 1
-
-#cmakedefine GIT_WIN32_LEAKCHECK 1
-
-#cmakedefine GIT_ARCH_64 1
-#cmakedefine GIT_ARCH_32 1
-
-#cmakedefine GIT_USE_STAT_MTIM 1
-#cmakedefine GIT_USE_STAT_MTIMESPEC 1
-#cmakedefine GIT_USE_STAT_MTIME_NSEC 1
-#cmakedefine GIT_USE_FUTIMENS 1
-
-#cmakedefine GIT_USE_QSORT_R_BSD 1
-#cmakedefine GIT_USE_QSORT_R_GNU 1
-#cmakedefine GIT_USE_QSORT_S 1
-
-#cmakedefine GIT_REGEX_REGCOMP_L 1
-#cmakedefine GIT_REGEX_REGCOMP 1
-#cmakedefine GIT_REGEX_PCRE 1
-#cmakedefine GIT_REGEX_PCRE2 1
-#cmakedefine GIT_REGEX_BUILTIN 1
-
-#cmakedefine GIT_SHA1_COLLISIONDETECT 1
-#cmakedefine GIT_SHA1_WIN32 1
-#cmakedefine GIT_SHA1_COMMON_CRYPTO 1
-#cmakedefine GIT_SHA1_OPENSSL 1
-#cmakedefine GIT_SHA1_MBEDTLS 1
-
-#endif
diff --git a/src/util/CMakeLists.txt b/src/util/CMakeLists.txt
new file mode 100644
index 000000000..ea2df0a56
--- /dev/null
+++ b/src/util/CMakeLists.txt
@@ -0,0 +1,59 @@
+# util: a shared library for common utility functions for libgit2 projects
+
+add_library(util OBJECT)
+set_target_properties(util PROPERTIES C_STANDARD 90)
+set_target_properties(util PROPERTIES C_EXTENSIONS OFF)
+
+set(UTIL_INCLUDES
+	"${PROJECT_BINARY_DIR}/src"
+	"${PROJECT_SOURCE_DIR}/src/util"
+	"${PROJECT_SOURCE_DIR}/include")
+
+file(GLOB UTIL_SRC *.c *.h allocators/*.c allocators/*.h hash/sha1.h)
+list(SORT UTIL_SRC)
+
+#
+# Platform specific sources
+#
+
+if(WIN32 AND NOT CYGWIN)
+	file(GLOB UTIL_SRC_OS win32/*.c win32/*.h)
+	list(SORT UTIL_SRC_OS)
+elseif(NOT AMIGA)
+	file(GLOB UTIL_SRC_OS unix/*.c unix/*.h)
+	list(SORT UTIL_SRC_OS)
+endif()
+
+#
+# Hash backend selection
+#
+
+if(USE_SHA1 STREQUAL "CollisionDetection")
+	file(GLOB UTIL_SRC_HASH hash/sha1/collisiondetect.* hash/sha1/sha1dc/*)
+	target_compile_definitions(util PRIVATE SHA1DC_NO_STANDARD_INCLUDES=1)
+        target_compile_definitions(util PRIVATE SHA1DC_CUSTOM_INCLUDE_SHA1_C=\"git2_util.h\")
+        target_compile_definitions(util PRIVATE SHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C=\"git2_util.h\")
+elseif(USE_SHA1 STREQUAL "OpenSSL")
+	file(GLOB UTIL_SRC_HASH hash/sha1/openssl.*)
+elseif(USE_SHA1 STREQUAL "CommonCrypto")
+	file(GLOB UTIL_SRC_HASH hash/sha1/common_crypto.*)
+elseif(USE_SHA1 STREQUAL "mbedTLS")
+	file(GLOB UTIL_SRC_HASH hash/sha1/mbedtls.*)
+elseif(USE_SHA1 STREQUAL "Win32")
+	file(GLOB UTIL_SRC_HASH hash/sha1/win32.*)
+elseif(USE_SHA1 STREQUAL "Generic")
+	file(GLOB UTIL_SRC_HASH hash/sha1/generic.*)
+else()
+	message(FATAL_ERROR "Asked for unknown SHA1 backend: ${USE_SHA1}")
+endif()
+
+list(SORT UTIL_SRC_HASH)
+
+#
+# Build the library
+#
+
+target_sources(util PRIVATE ${UTIL_SRC} ${UTIL_SRC_OS} ${UTIL_SRC_HASH})
+
+target_include_directories(util PRIVATE ${UTIL_INCLUDES} ${LIBGIT2_DEPENDENCY_INCLUDES} PUBLIC ${libgit2_SOURCE_DIR}/include)
+target_include_directories(util SYSTEM PRIVATE ${LIBGIT2_SYSTEM_INCLUDES})
diff --git a/src/libgit2/alloc.c b/src/util/alloc.c
index 2820d84a2..2820d84a2 100644
--- a/src/libgit2/alloc.c
+++ b/src/util/alloc.c
diff --git a/src/libgit2/alloc.h b/src/util/alloc.h
index 04fb7e101..04fb7e101 100644
--- a/src/libgit2/alloc.h
+++ b/src/util/alloc.h
diff --git a/src/libgit2/allocators/failalloc.c b/src/util/allocators/failalloc.c
index 5257d1dec..5257d1dec 100644
--- a/src/libgit2/allocators/failalloc.c
+++ b/src/util/allocators/failalloc.c
diff --git a/src/libgit2/allocators/failalloc.h b/src/util/allocators/failalloc.h
index 6115e51e7..91264a0bb 100644
--- a/src/libgit2/allocators/failalloc.h
+++ b/src/util/allocators/failalloc.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_allocators_failalloc_h__
 #define INCLUDE_allocators_failalloc_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 extern void *git_failalloc_malloc(size_t len, const char *file, int line);
 extern void *git_failalloc_calloc(size_t nelem, size_t elsize, const char *file, int line);
diff --git a/src/libgit2/allocators/stdalloc.c b/src/util/allocators/stdalloc.c
index 2b36d9f3d..2b36d9f3d 100644
--- a/src/libgit2/allocators/stdalloc.c
+++ b/src/util/allocators/stdalloc.c
diff --git a/src/libgit2/allocators/stdalloc.h b/src/util/allocators/stdalloc.h
index fa23fe6e3..955038cb0 100644
--- a/src/libgit2/allocators/stdalloc.h
+++ b/src/util/allocators/stdalloc.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_allocators_stdalloc_h__
 #define INCLUDE_allocators_stdalloc_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "alloc.h"
 
diff --git a/src/libgit2/allocators/win32_leakcheck.c b/src/util/allocators/win32_leakcheck.c
index fe06a14af..fe06a14af 100644
--- a/src/libgit2/allocators/win32_leakcheck.c
+++ b/src/util/allocators/win32_leakcheck.c
diff --git a/src/libgit2/allocators/win32_leakcheck.h b/src/util/allocators/win32_leakcheck.h
index 089690f90..edcd9307f 100644
--- a/src/libgit2/allocators/win32_leakcheck.h
+++ b/src/util/allocators/win32_leakcheck.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_allocators_win32_leakcheck_h
 #define INCLUDE_allocators_win32_leakcheck_h
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "alloc.h"
 
diff --git a/src/libgit2/array.h b/src/util/array.h
index e97688b36..cbab52ad1 100644
--- a/src/libgit2/array.h
+++ b/src/util/array.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_array_h__
 #define INCLUDE_array_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 /*
  * Use this to declare a typesafe resizable array of items, a la:
diff --git a/src/libgit2/assert_safe.h b/src/util/assert_safe.h
index 8c261100f..8c261100f 100644
--- a/src/libgit2/assert_safe.h
+++ b/src/util/assert_safe.h
diff --git a/src/libgit2/bitvec.h b/src/util/bitvec.h
index 544832d95..544832d95 100644
--- a/src/libgit2/bitvec.h
+++ b/src/util/bitvec.h
diff --git a/src/libgit2/cc-compat.h b/src/util/cc-compat.h
index a0971e86c..a0971e86c 100644
--- a/src/libgit2/cc-compat.h
+++ b/src/util/cc-compat.h
diff --git a/src/libgit2/date.c b/src/util/date.c
index 0e5ffc96b..4d757e21a 100644
--- a/src/libgit2/date.c
+++ b/src/util/date.c
@@ -1,10 +1,11 @@
 /*
- * GIT - The information manager from hell
+ * Copyright (C) the libgit2 contributors. All rights reserved.
  *
- * Copyright (C) Linus Torvalds, 2005
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 
 #ifndef GIT_WIN32
 #include <sys/time.h>
diff --git a/src/libgit2/date.h b/src/util/date.h
index 7ebd3c30e..7ebd3c30e 100644
--- a/src/libgit2/date.h
+++ b/src/util/date.h
diff --git a/src/libgit2/filebuf.c b/src/util/filebuf.c
index eafcba3bd..e014d43b2 100644
--- a/src/libgit2/filebuf.c
+++ b/src/util/filebuf.c
@@ -65,7 +65,7 @@ static int lock_file(git_filebuf *file, int flags, mode_t mode)
 
 	if ((flags & GIT_FILEBUF_APPEND) && git_fs_path_exists(file->path_original) == true) {
 		git_file source;
-		char buffer[FILEIO_BUFSIZE];
+		char buffer[GIT_BUFSIZE_FILEIO];
 		ssize_t read_bytes;
 		int error = 0;
 
diff --git a/src/libgit2/filebuf.h b/src/util/filebuf.h
index adbb19936..4a61ae4e3 100644
--- a/src/libgit2/filebuf.h
+++ b/src/util/filebuf.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_filebuf_h__
 #define INCLUDE_filebuf_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "futils.h"
 #include "hash.h"
diff --git a/src/libgit2/fs_path.c b/src/util/fs_path.c
index 7a657778a..920c39073 100644
--- a/src/libgit2/fs_path.c
+++ b/src/util/fs_path.c
@@ -7,8 +7,9 @@
 
 #include "fs_path.h"
 
+#include "git2_util.h"
+#include "futils.h"
 #include "posix.h"
-#include "repository.h"
 #ifdef GIT_WIN32
 #include "win32/posix.h"
 #include "win32/w32_buffer.h"
@@ -21,6 +22,13 @@
 #include <stdio.h>
 #include <ctype.h>
 
+#define ensure_error_set(code) do { \
+		const git_error *e = git_error_last(); \
+		if (!e || !e->message) \
+			git_error_set(e ? e->klass : GIT_ERROR_CALLBACK, \
+				"filesystem callback returned %d", code); \
+	} while(0)
+
 static int dos_drive_prefix_length(const char *path)
 {
 	int i;
@@ -530,7 +538,7 @@ int git_fs_path_walk_up(
 	if (!scan) {
 		error = cb(data, "");
 		if (error)
-			git_error_set_after_callback(error);
+			ensure_error_set(error);
 		return error;
 	}
 
@@ -543,7 +551,7 @@ int git_fs_path_walk_up(
 		iter.ptr[scan] = oldc;
 
 		if (error) {
-			git_error_set_after_callback(error);
+			ensure_error_set(error);
 			break;
 		}
 
@@ -563,7 +571,7 @@ int git_fs_path_walk_up(
 	if (!error && stop == 0 && iter.ptr[0] != '/') {
 		error = cb(data, "");
 		if (error)
-			git_error_set_after_callback(error);
+			ensure_error_set(error);
 	}
 
 	return error;
@@ -1167,7 +1175,7 @@ int git_fs_path_direach(
 		/* Only set our own error if the callback did not set one already */
 		if (error != 0) {
 			if (!git_error_last())
-				git_error_set_after_callback(error);
+				ensure_error_set(error);
 
 			break;
 		}
diff --git a/src/libgit2/fs_path.h b/src/util/fs_path.h
index 222c44abc..bb840c43c 100644
--- a/src/libgit2/fs_path.h
+++ b/src/util/fs_path.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_fs_path_h__
 #define INCLUDE_fs_path_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "posix.h"
 #include "str.h"
diff --git a/src/libgit2/futils.c b/src/util/futils.c
index 42c35955e..2b0dbf362 100644
--- a/src/libgit2/futils.c
+++ b/src/util/futils.c
@@ -856,7 +856,7 @@ int git_futils_fake_symlink(const char *target, const char *path)
 static int cp_by_fd(int ifd, int ofd, bool close_fd_when_done)
 {
 	int error = 0;
-	char buffer[FILEIO_BUFSIZE];
+	char buffer[GIT_BUFSIZE_FILEIO];
 	ssize_t len = 0;
 
 	while (!error && (len = p_read(ifd, buffer, sizeof(buffer))) > 0)
diff --git a/src/libgit2/futils.h b/src/util/futils.h
index a82ec41cc..fb1afcbd5 100644
--- a/src/libgit2/futils.h
+++ b/src/util/futils.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_futils_h__
 #define INCLUDE_futils_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "map.h"
 #include "posix.h"
diff --git a/src/util/git2_util.h b/src/util/git2_util.h
new file mode 100644
index 000000000..ad3f1c71f
--- /dev/null
+++ b/src/util/git2_util.h
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git2_util_h__
+#define INCLUDE_git2_util_h__
+
+#ifndef LIBGIT2_NO_FEATURES_H
+# include "git2/sys/features.h"
+#endif
+
+#include "git2/common.h"
+#include "cc-compat.h"
+
+typedef struct git_str git_str;
+
+/** Declare a function as always inlined. */
+#if defined(_MSC_VER)
+# define GIT_INLINE(type) static __inline type
+#elif defined(__GNUC__)
+# define GIT_INLINE(type) static __inline__ type
+#else
+# define GIT_INLINE(type) static type
+#endif
+
+/** Support for gcc/clang __has_builtin intrinsic */
+#ifndef __has_builtin
+# define __has_builtin(x) 0
+#endif
+
+/**
+ * Declare that a function's return value must be used.
+ *
+ * Used mostly to guard against potential silent bugs at runtime. This is
+ * recommended to be added to functions that:
+ *
+ * - Allocate / reallocate memory. This prevents memory leaks or errors where
+ *   buffers are expected to have grown to a certain size, but could not be
+ *   resized.
+ * - Acquire locks. When a lock cannot be acquired, that will almost certainly
+ *   cause a data race / undefined behavior.
+ */
+#if defined(__GNUC__)
+# define GIT_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
+#else
+# define GIT_WARN_UNUSED_RESULT
+#endif
+
+#include <assert.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifdef GIT_WIN32
+
+# include <io.h>
+# include <direct.h>
+# include <winsock2.h>
+# include <windows.h>
+# include <ws2tcpip.h>
+# include "win32/msvc-compat.h"
+# include "win32/mingw-compat.h"
+# include "win32/win32-compat.h"
+# include "win32/w32_common.h"
+# include "win32/version.h"
+# include "win32/error.h"
+# ifdef GIT_THREADS
+#  include "win32/thread.h"
+# endif
+
+#else
+
+# include <unistd.h>
+# include <strings.h>
+# ifdef GIT_THREADS
+#	include <pthread.h>
+#	include <sched.h>
+# endif
+
+#define GIT_LIBGIT2_CALL
+#define GIT_SYSTEM_CALL
+
+#ifdef GIT_USE_STAT_ATIMESPEC
+# define st_atim st_atimespec
+# define st_ctim st_ctimespec
+# define st_mtim st_mtimespec
+#endif
+
+# include <arpa/inet.h>
+
+#endif
+
+#include "git2/types.h"
+#include "git2/errors.h"
+#include "thread.h"
+#include "integer.h"
+#include "assert_safe.h"
+
+#include "posix.h"
+
+#define GIT_BUFSIZE_DEFAULT 65536
+#define GIT_BUFSIZE_FILEIO GIT_BUFSIZE_DEFAULT
+#define GIT_BUFSIZE_FILTERIO GIT_BUFSIZE_DEFAULT
+#define GIT_BUFSIZE_NETIO GIT_BUFSIZE_DEFAULT
+
+
+/**
+ * Check a pointer allocation result, returning -1 if it failed.
+ */
+#define GIT_ERROR_CHECK_ALLOC(ptr) do { \
+	if ((ptr) == NULL) { return -1; } \
+	} while(0)
+
+/**
+ * Check a buffer allocation result, returning -1 if it failed.
+ */
+#define GIT_ERROR_CHECK_ALLOC_STR(buf) do { \
+	if ((void *)(buf) == NULL || git_str_oom(buf)) { return -1; } \
+	} while(0)
+
+/**
+ * Check a return value and propagate result if non-zero.
+ */
+#define GIT_ERROR_CHECK_ERROR(code) \
+	do { int _err = (code); if (_err) return _err; } while (0)
+
+
+/** Check for additive overflow, setting an error if would occur. */
+#define GIT_ADD_SIZET_OVERFLOW(out, one, two) \
+	(git__add_sizet_overflow(out, one, two) ? (git_error_set_oom(), 1) : 0)
+
+/** Check for additive overflow, setting an error if would occur. */
+#define GIT_MULTIPLY_SIZET_OVERFLOW(out, nelem, elsize) \
+	(git__multiply_sizet_overflow(out, nelem, elsize) ? (git_error_set_oom(), 1) : 0)
+
+/** Check for additive overflow, failing if it would occur. */
+#define GIT_ERROR_CHECK_ALLOC_ADD(out, one, two) \
+	if (GIT_ADD_SIZET_OVERFLOW(out, one, two)) { return -1; }
+
+#define GIT_ERROR_CHECK_ALLOC_ADD3(out, one, two, three) \
+	if (GIT_ADD_SIZET_OVERFLOW(out, one, two) || \
+		GIT_ADD_SIZET_OVERFLOW(out, *(out), three)) { return -1; }
+
+#define GIT_ERROR_CHECK_ALLOC_ADD4(out, one, two, three, four) \
+	if (GIT_ADD_SIZET_OVERFLOW(out, one, two) || \
+		GIT_ADD_SIZET_OVERFLOW(out, *(out), three) || \
+		GIT_ADD_SIZET_OVERFLOW(out, *(out), four)) { return -1; }
+
+#define GIT_ERROR_CHECK_ALLOC_ADD5(out, one, two, three, four, five) \
+	if (GIT_ADD_SIZET_OVERFLOW(out, one, two) || \
+		GIT_ADD_SIZET_OVERFLOW(out, *(out), three) || \
+		GIT_ADD_SIZET_OVERFLOW(out, *(out), four) || \
+		GIT_ADD_SIZET_OVERFLOW(out, *(out), five)) { return -1; }
+
+/** Check for multiplicative overflow, failing if it would occur. */
+#define GIT_ERROR_CHECK_ALLOC_MULTIPLY(out, nelem, elsize) \
+	if (GIT_MULTIPLY_SIZET_OVERFLOW(out, nelem, elsize)) { return -1; }
+
+#include "util.h"
+
+#endif
diff --git a/src/libgit2/hash.c b/src/util/hash.c
index 98ceb05d2..98ceb05d2 100644
--- a/src/libgit2/hash.c
+++ b/src/util/hash.c
diff --git a/src/libgit2/hash.h b/src/util/hash.h
index 507c1cb25..5f1386563 100644
--- a/src/libgit2/hash.h
+++ b/src/util/hash.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_hash_h__
 #define INCLUDE_hash_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "hash/sha1.h"
 
diff --git a/src/libgit2/hash/sha1.h b/src/util/hash/sha1.h
index 4b4dae3f8..9d32bce42 100644
--- a/src/libgit2/hash/sha1.h
+++ b/src/util/hash/sha1.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_hash_sha1_h__
 #define INCLUDE_hash_sha1_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 typedef struct git_hash_sha1_ctx git_hash_sha1_ctx;
 
diff --git a/src/libgit2/hash/sha1/collisiondetect.c b/src/util/hash/sha1/collisiondetect.c
index ec7059c4c..ec7059c4c 100644
--- a/src/libgit2/hash/sha1/collisiondetect.c
+++ b/src/util/hash/sha1/collisiondetect.c
diff --git a/src/libgit2/hash/sha1/collisiondetect.h b/src/util/hash/sha1/collisiondetect.h
index eb88e86c1..eb88e86c1 100644
--- a/src/libgit2/hash/sha1/collisiondetect.h
+++ b/src/util/hash/sha1/collisiondetect.h
diff --git a/src/libgit2/hash/sha1/common_crypto.c b/src/util/hash/sha1/common_crypto.c
index 9d608f449..9d608f449 100644
--- a/src/libgit2/hash/sha1/common_crypto.c
+++ b/src/util/hash/sha1/common_crypto.c
diff --git a/src/libgit2/hash/sha1/common_crypto.h b/src/util/hash/sha1/common_crypto.h
index a5fcfb33e..a5fcfb33e 100644
--- a/src/libgit2/hash/sha1/common_crypto.h
+++ b/src/util/hash/sha1/common_crypto.h
diff --git a/src/libgit2/hash/sha1/generic.c b/src/util/hash/sha1/generic.c
index 85b34c578..85b34c578 100644
--- a/src/libgit2/hash/sha1/generic.c
+++ b/src/util/hash/sha1/generic.c
diff --git a/src/libgit2/hash/sha1/generic.h b/src/util/hash/sha1/generic.h
index 53fc0823e..53fc0823e 100644
--- a/src/libgit2/hash/sha1/generic.h
+++ b/src/util/hash/sha1/generic.h
diff --git a/src/libgit2/hash/sha1/mbedtls.c b/src/util/hash/sha1/mbedtls.c
index 56016bec8..56016bec8 100644
--- a/src/libgit2/hash/sha1/mbedtls.c
+++ b/src/util/hash/sha1/mbedtls.c
diff --git a/src/libgit2/hash/sha1/mbedtls.h b/src/util/hash/sha1/mbedtls.h
index 15f7462a4..15f7462a4 100644
--- a/src/libgit2/hash/sha1/mbedtls.h
+++ b/src/util/hash/sha1/mbedtls.h
diff --git a/src/libgit2/hash/sha1/openssl.c b/src/util/hash/sha1/openssl.c
index 64bf99b3c..64bf99b3c 100644
--- a/src/libgit2/hash/sha1/openssl.c
+++ b/src/util/hash/sha1/openssl.c
diff --git a/src/libgit2/hash/sha1/openssl.h b/src/util/hash/sha1/openssl.h
index a223ca03e..a223ca03e 100644
--- a/src/libgit2/hash/sha1/openssl.h
+++ b/src/util/hash/sha1/openssl.h
diff --git a/src/libgit2/hash/sha1/sha1dc/sha1.c b/src/util/hash/sha1/sha1dc/sha1.c
index 929822728..929822728 100644
--- a/src/libgit2/hash/sha1/sha1dc/sha1.c
+++ b/src/util/hash/sha1/sha1dc/sha1.c
diff --git a/src/libgit2/hash/sha1/sha1dc/sha1.h b/src/util/hash/sha1/sha1dc/sha1.h
index 1e4e94be5..1e4e94be5 100644
--- a/src/libgit2/hash/sha1/sha1dc/sha1.h
+++ b/src/util/hash/sha1/sha1dc/sha1.h
diff --git a/src/libgit2/hash/sha1/sha1dc/ubc_check.c b/src/util/hash/sha1/sha1dc/ubc_check.c
index b3beff2af..b3beff2af 100644
--- a/src/libgit2/hash/sha1/sha1dc/ubc_check.c
+++ b/src/util/hash/sha1/sha1dc/ubc_check.c
diff --git a/src/libgit2/hash/sha1/sha1dc/ubc_check.h b/src/util/hash/sha1/sha1dc/ubc_check.h
index d7e17dc73..d7e17dc73 100644
--- a/src/libgit2/hash/sha1/sha1dc/ubc_check.h
+++ b/src/util/hash/sha1/sha1dc/ubc_check.h
diff --git a/src/libgit2/hash/sha1/win32.c b/src/util/hash/sha1/win32.c
index b89dfbad8..b89dfbad8 100644
--- a/src/libgit2/hash/sha1/win32.c
+++ b/src/util/hash/sha1/win32.c
diff --git a/src/libgit2/hash/sha1/win32.h b/src/util/hash/sha1/win32.h
index 791d20a42..791d20a42 100644
--- a/src/libgit2/hash/sha1/win32.h
+++ b/src/util/hash/sha1/win32.h
diff --git a/src/libgit2/integer.h b/src/util/integer.h
index 63277177b..63277177b 100644
--- a/src/libgit2/integer.h
+++ b/src/util/integer.h
diff --git a/src/libgit2/khash.h b/src/util/khash.h
index c9b7f131f..c9b7f131f 100644
--- a/src/libgit2/khash.h
+++ b/src/util/khash.h
diff --git a/src/libgit2/map.h b/src/util/map.h
index 01931d199..c101e46f6 100644
--- a/src/libgit2/map.h
+++ b/src/util/map.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_map_h__
 #define INCLUDE_map_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 
 /* p_mmap() prot values */
diff --git a/src/libgit2/net.c b/src/util/net.c
index a76fd1d7c..b2236daf8 100644
--- a/src/libgit2/net.c
+++ b/src/util/net.c
@@ -6,7 +6,6 @@
  */
 
 #include "net.h"
-#include "netops.h"
 
 #include <ctype.h>
 
diff --git a/src/libgit2/net.h b/src/util/net.h
index 499315e6c..88030a952 100644
--- a/src/libgit2/net.h
+++ b/src/util/net.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_net_h__
 #define INCLUDE_net_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 typedef struct git_net_url {
 	char *scheme;
diff --git a/src/libgit2/pool.c b/src/util/pool.c
index 16ffa398d..16ffa398d 100644
--- a/src/libgit2/pool.c
+++ b/src/util/pool.c
diff --git a/src/libgit2/pool.h b/src/util/pool.h
index cecb84665..0238431b0 100644
--- a/src/libgit2/pool.h
+++ b/src/util/pool.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_pool_h__
 #define INCLUDE_pool_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "vector.h"
 
diff --git a/src/libgit2/posix.c b/src/util/posix.c
index b1f85dc94..b1f85dc94 100644
--- a/src/libgit2/posix.c
+++ b/src/util/posix.c
diff --git a/src/libgit2/posix.h b/src/util/posix.h
index e6f603078..c8f8cd9d2 100644
--- a/src/libgit2/posix.h
+++ b/src/util/posix.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_posix_h__
 #define INCLUDE_posix_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include <stdlib.h>
 #include <fcntl.h>
diff --git a/src/libgit2/pqueue.c b/src/util/pqueue.c
index 3820e999c..3820e999c 100644
--- a/src/libgit2/pqueue.c
+++ b/src/util/pqueue.c
diff --git a/src/libgit2/pqueue.h b/src/util/pqueue.h
index 4db74ea03..97232b4a9 100644
--- a/src/libgit2/pqueue.h
+++ b/src/util/pqueue.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_pqueue_h__
 #define INCLUDE_pqueue_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "vector.h"
 
diff --git a/src/rand.c b/src/util/rand.c
index 0a208134e..432494902 100644
--- a/src/rand.c
+++ b/src/util/rand.c
@@ -6,7 +6,7 @@ worldwide. This software is distributed without any warranty.
 
 See <http://creativecommons.org/publicdomain/zero/1.0/>. */
 
-#include "common.h"
+#include "git2_util.h"
 #include "rand.h"
 #include "runtime.h"
 
diff --git a/src/rand.h b/src/util/rand.h
index 2e60561e5..fa0619aa2 100644
--- a/src/rand.h
+++ b/src/util/rand.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_rand_h__
 #define INCLUDE_rand_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 /**
  * Initialize the random number generation subsystem.  This will
diff --git a/src/libgit2/regexp.c b/src/util/regexp.c
index 2569dea0a..2569dea0a 100644
--- a/src/libgit2/regexp.c
+++ b/src/util/regexp.c
diff --git a/src/libgit2/regexp.h b/src/util/regexp.h
index 2592ef383..d0862b107 100644
--- a/src/libgit2/regexp.h
+++ b/src/util/regexp.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_regexp_h__
 #define INCLUDE_regexp_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #if defined(GIT_REGEX_BUILTIN) || defined(GIT_REGEX_PCRE)
 # include "pcre.h"
diff --git a/src/libgit2/runtime.c b/src/util/runtime.c
index c05dee8b9..a7711ffc4 100644
--- a/src/libgit2/runtime.c
+++ b/src/util/runtime.c
@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 #include "runtime.h"
 
 static git_runtime_shutdown_fn shutdown_callback[32];
diff --git a/src/libgit2/runtime.h b/src/util/runtime.h
index 24ac58ee9..6cbfd6043 100644
--- a/src/libgit2/runtime.h
+++ b/src/util/runtime.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_runtime_h__
 #define INCLUDE_runtime_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 typedef int (*git_runtime_init_fn)(void);
 typedef void (*git_runtime_shutdown_fn)(void);
diff --git a/src/libgit2/sortedcache.c b/src/util/sortedcache.c
index 7ff900efe..7ff900efe 100644
--- a/src/libgit2/sortedcache.c
+++ b/src/util/sortedcache.c
diff --git a/src/libgit2/sortedcache.h b/src/util/sortedcache.h
index ef260a093..3eee4659f 100644
--- a/src/libgit2/sortedcache.h
+++ b/src/util/sortedcache.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_sorted_cache_h__
 #define INCLUDE_sorted_cache_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "util.h"
 #include "futils.h"
diff --git a/src/libgit2/str.c b/src/util/str.c
index 0d405bfda..0d405bfda 100644
--- a/src/libgit2/str.c
+++ b/src/util/str.c
diff --git a/src/libgit2/str.h b/src/util/str.h
index ef769ce2f..588e6fc22 100644
--- a/src/libgit2/str.h
+++ b/src/util/str.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_str_h__
 #define INCLUDE_str_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 struct git_str {
 	char *ptr;
diff --git a/src/libgit2/strmap.c b/src/util/strmap.c
index c6e5b6dc7..c6e5b6dc7 100644
--- a/src/libgit2/strmap.c
+++ b/src/util/strmap.c
diff --git a/src/libgit2/strmap.h b/src/util/strmap.h
index 9f5e4cc8b..b64d3dcb5 100644
--- a/src/libgit2/strmap.h
+++ b/src/util/strmap.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_strmap_h__
 #define INCLUDE_strmap_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 /** A map with C strings as key. */
 typedef struct kh_str_s git_strmap;
diff --git a/src/libgit2/strnlen.h b/src/util/strnlen.h
index eecfe3c02..eecfe3c02 100644
--- a/src/libgit2/strnlen.h
+++ b/src/util/strnlen.h
diff --git a/src/libgit2/thread.c b/src/util/thread.c
index 3171771d7..bc7364f8c 100644
--- a/src/libgit2/thread.c
+++ b/src/util/thread.c
@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 
 #if !defined(GIT_THREADS)
 
diff --git a/src/libgit2/thread.h b/src/util/thread.h
index 4bbac9fd8..4bbac9fd8 100644
--- a/src/libgit2/thread.h
+++ b/src/util/thread.h
diff --git a/src/libgit2/tsort.c b/src/util/tsort.c
index 045efad23..2ef03d03a 100644
--- a/src/libgit2/tsort.c
+++ b/src/util/tsort.c
@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 
 /**
  * An array-of-pointers implementation of Python's Timsort
diff --git a/src/libgit2/unix/map.c b/src/util/unix/map.c
index 23fcb786e..933077689 100644
--- a/src/libgit2/unix/map.c
+++ b/src/util/unix/map.c
@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 
 #if !defined(GIT_WIN32) && !defined(NO_MMAP)
 
diff --git a/src/libgit2/unix/posix.h b/src/util/unix/posix.h
index 49065e533..778477e8e 100644
--- a/src/libgit2/unix/posix.h
+++ b/src/util/unix/posix.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_unix_posix_h__
 #define INCLUDE_unix_posix_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include <stdio.h>
 #include <dirent.h>
diff --git a/src/libgit2/unix/pthread.h b/src/util/unix/pthread.h
index 55f4ae227..55f4ae227 100644
--- a/src/libgit2/unix/pthread.h
+++ b/src/util/unix/pthread.h
diff --git a/src/libgit2/unix/realpath.c b/src/util/unix/realpath.c
index f1ca669f7..9e31a63b9 100644
--- a/src/libgit2/unix/realpath.c
+++ b/src/util/unix/realpath.c
@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 
 #ifndef GIT_WIN32
 
diff --git a/src/libgit2/utf8.c b/src/util/utf8.c
index 77065cb71..c566fdf20 100644
--- a/src/libgit2/utf8.c
+++ b/src/util/utf8.c
@@ -7,7 +7,7 @@
 
 #include "utf8.h"
 
-#include "common.h"
+#include "git2_util.h"
 
 /*
  * git_utf8_iterate is taken from the utf8proc project,
diff --git a/src/libgit2/utf8.h b/src/util/utf8.h
index dff91b294..753ab07e2 100644
--- a/src/libgit2/utf8.h
+++ b/src/util/utf8.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_utf8_h__
 #define INCLUDE_utf8_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 /*
  * Iterate through an UTF-8 string, yielding one codepoint at a time.
diff --git a/src/libgit2/util.c b/src/util/util.c
index e06d4ca09..aee95fddf 100644
--- a/src/libgit2/util.c
+++ b/src/util/util.c
@@ -7,7 +7,7 @@
 
 #include "util.h"
 
-#include "common.h"
+#include "git2_util.h"
 
 #ifdef GIT_WIN32
 # include "win32/utf-conv.h"
diff --git a/src/libgit2/util.h b/src/util/util.h
index 141779ade..8d6d1d6b6 100644
--- a/src/libgit2/util.h
+++ b/src/util/util.h
@@ -12,7 +12,7 @@
 #endif
 
 #include "str.h"
-#include "common.h"
+#include "git2_util.h"
 #include "strnlen.h"
 #include "thread.h"
 
diff --git a/src/libgit2/varint.c b/src/util/varint.c
index 9ffc1d744..9ffc1d744 100644
--- a/src/libgit2/varint.c
+++ b/src/util/varint.c
diff --git a/src/libgit2/varint.h b/src/util/varint.h
index 652e22486..79b8f5548 100644
--- a/src/libgit2/varint.h
+++ b/src/util/varint.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_varint_h__
 #define INCLUDE_varint_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include <stdint.h>
 
diff --git a/src/libgit2/vector.c b/src/util/vector.c
index 4a4bc8c0e..4a4bc8c0e 100644
--- a/src/libgit2/vector.c
+++ b/src/util/vector.c
diff --git a/src/libgit2/vector.h b/src/util/vector.h
index ae3c79a4c..e50cdfefc 100644
--- a/src/libgit2/vector.h
+++ b/src/util/vector.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_vector_h__
 #define INCLUDE_vector_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 typedef int (*git_vector_cmp)(const void *, const void *);
 
diff --git a/src/libgit2/wildmatch.c b/src/util/wildmatch.c
index a894e4841..a894e4841 100644
--- a/src/libgit2/wildmatch.c
+++ b/src/util/wildmatch.c
diff --git a/src/libgit2/wildmatch.h b/src/util/wildmatch.h
index 44bb575a6..f20640500 100644
--- a/src/libgit2/wildmatch.h
+++ b/src/util/wildmatch.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_wildmatch_h__
 #define INCLUDE_wildmatch_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #define WM_CASEFOLD 1
 #define WM_PATHNAME 2
diff --git a/src/libgit2/win32/dir.c b/src/util/win32/dir.c
index 44052caf0..44052caf0 100644
--- a/src/libgit2/win32/dir.c
+++ b/src/util/win32/dir.c
diff --git a/src/libgit2/win32/dir.h b/src/util/win32/dir.h
index acd64729e..810111534 100644
--- a/src/libgit2/win32/dir.h
+++ b/src/util/win32/dir.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_win32_dir_h__
 #define INCLUDE_win32_dir_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "w32_util.h"
 
diff --git a/src/libgit2/win32/error.c b/src/util/win32/error.c
index 3a52fb5a9..3a52fb5a9 100644
--- a/src/libgit2/win32/error.c
+++ b/src/util/win32/error.c
diff --git a/src/libgit2/win32/error.h b/src/util/win32/error.h
index 9e81141ce..fd53b7f99 100644
--- a/src/libgit2/win32/error.h
+++ b/src/util/win32/error.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_win32_error_h__
 #define INCLUDE_win32_error_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 extern char *git_win32_get_error_message(DWORD error_code);
 
diff --git a/src/libgit2/win32/findfile.c b/src/util/win32/findfile.c
index 725a90167..725a90167 100644
--- a/src/libgit2/win32/findfile.c
+++ b/src/util/win32/findfile.c
diff --git a/src/libgit2/win32/findfile.h b/src/util/win32/findfile.h
index 61fb7dbad..7b191d1fe 100644
--- a/src/libgit2/win32/findfile.h
+++ b/src/util/win32/findfile.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_win32_findfile_h__
 #define INCLUDE_win32_findfile_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 /** Sets the mock registry root for Git for Windows for testing. */
 extern int git_win32__set_registry_system_dir(const wchar_t *mock_sysdir);
diff --git a/src/libgit2/win32/map.c b/src/util/win32/map.c
index 2aabc9b15..52e1363ea 100644
--- a/src/libgit2/win32/map.c
+++ b/src/util/win32/map.c
@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "map.h"
 #include <errno.h>
diff --git a/src/libgit2/win32/mingw-compat.h b/src/util/win32/mingw-compat.h
index aa2bef98d..aa2bef98d 100644
--- a/src/libgit2/win32/mingw-compat.h
+++ b/src/util/win32/mingw-compat.h
diff --git a/src/libgit2/win32/msvc-compat.h b/src/util/win32/msvc-compat.h
index 03f9f36dc..03f9f36dc 100644
--- a/src/libgit2/win32/msvc-compat.h
+++ b/src/util/win32/msvc-compat.h
diff --git a/src/libgit2/win32/path_w32.c b/src/util/win32/path_w32.c
index d9fc8292b..d9fc8292b 100644
--- a/src/libgit2/win32/path_w32.c
+++ b/src/util/win32/path_w32.c
diff --git a/src/libgit2/win32/path_w32.h b/src/util/win32/path_w32.h
index 837b11ebd..b241d5c8a 100644
--- a/src/libgit2/win32/path_w32.h
+++ b/src/util/win32/path_w32.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_win32_path_w32_h__
 #define INCLUDE_win32_path_w32_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 /**
  * Create a Win32 path (in UCS-2 format) from a UTF-8 string.  If the given
diff --git a/src/libgit2/win32/posix.h b/src/util/win32/posix.h
index 578347f15..03fa2ac52 100644
--- a/src/libgit2/win32/posix.h
+++ b/src/util/win32/posix.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_win32_posix_h__
 #define INCLUDE_win32_posix_h__
 
-#include "common.h"
+#include "git2_util.h"
 #include "../posix.h"
 #include "win32-compat.h"
 #include "path_w32.h"
diff --git a/src/libgit2/win32/posix_w32.c b/src/util/win32/posix_w32.c
index 5f7cd0c26..5862e5c9a 100644
--- a/src/libgit2/win32/posix_w32.c
+++ b/src/util/win32/posix_w32.c
@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "../posix.h"
 #include "../futils.h"
diff --git a/src/libgit2/win32/precompiled.c b/src/util/win32/precompiled.c
index 5f656a45d..5f656a45d 100644
--- a/src/libgit2/win32/precompiled.c
+++ b/src/util/win32/precompiled.c
diff --git a/src/libgit2/win32/precompiled.h b/src/util/win32/precompiled.h
index 806b1698a..1163c3d63 100644
--- a/src/libgit2/win32/precompiled.h
+++ b/src/util/win32/precompiled.h
@@ -1,4 +1,4 @@
-#include "common.h"
+#include "git2_util.h"
 
 #include <errno.h>
 #include <limits.h>
diff --git a/src/libgit2/win32/reparse.h b/src/util/win32/reparse.h
index 23312319f..23312319f 100644
--- a/src/libgit2/win32/reparse.h
+++ b/src/util/win32/reparse.h
diff --git a/src/libgit2/win32/thread.c b/src/util/win32/thread.c
index f5cacd320..f5cacd320 100644
--- a/src/libgit2/win32/thread.c
+++ b/src/util/win32/thread.c
diff --git a/src/libgit2/win32/thread.h b/src/util/win32/thread.h
index 8305036b4..184762e2a 100644
--- a/src/libgit2/win32/thread.h
+++ b/src/util/win32/thread.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_win32_thread_h__
 #define INCLUDE_win32_thread_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #if defined (_MSC_VER)
 #	define GIT_RESTRICT __restrict
diff --git a/src/libgit2/win32/utf-conv.c b/src/util/win32/utf-conv.c
index 4bde3023a..4bde3023a 100644
--- a/src/libgit2/win32/utf-conv.c
+++ b/src/util/win32/utf-conv.c
diff --git a/src/libgit2/win32/utf-conv.h b/src/util/win32/utf-conv.h
index 6090a4b35..120d647ef 100644
--- a/src/libgit2/win32/utf-conv.h
+++ b/src/util/win32/utf-conv.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_win32_utf_conv_h__
 #define INCLUDE_win32_utf_conv_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include <wchar.h>
 
diff --git a/src/libgit2/win32/version.h b/src/util/win32/version.h
index 79667697f..79667697f 100644
--- a/src/libgit2/win32/version.h
+++ b/src/util/win32/version.h
diff --git a/src/libgit2/win32/w32_buffer.c b/src/util/win32/w32_buffer.c
index 6fee8203c..6fee8203c 100644
--- a/src/libgit2/win32/w32_buffer.c
+++ b/src/util/win32/w32_buffer.c
diff --git a/src/libgit2/win32/w32_buffer.h b/src/util/win32/w32_buffer.h
index 4227296d8..68ea96035 100644
--- a/src/libgit2/win32/w32_buffer.h
+++ b/src/util/win32/w32_buffer.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_win32_w32_buffer_h__
 #define INCLUDE_win32_w32_buffer_h__
 
-#include "common.h"
+#include "git2_util.h"
 #include "str.h"
 
 /**
diff --git a/src/libgit2/win32/w32_common.h b/src/util/win32/w32_common.h
index c20b3e85e..c20b3e85e 100644
--- a/src/libgit2/win32/w32_common.h
+++ b/src/util/win32/w32_common.h
diff --git a/src/libgit2/win32/w32_leakcheck.c b/src/util/win32/w32_leakcheck.c
index 0f095de12..0f095de12 100644
--- a/src/libgit2/win32/w32_leakcheck.c
+++ b/src/util/win32/w32_leakcheck.c
diff --git a/src/libgit2/win32/w32_leakcheck.h b/src/util/win32/w32_leakcheck.h
index cb45e3675..82d863851 100644
--- a/src/libgit2/win32/w32_leakcheck.h
+++ b/src/util/win32/w32_leakcheck.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_win32_leakcheck_h__
 #define INCLUDE_win32_leakcheck_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 /* Initialize the win32 leak checking system. */
 int git_win32_leakcheck_global_init(void);
diff --git a/src/libgit2/win32/w32_util.c b/src/util/win32/w32_util.c
index fe4b75bae..fe4b75bae 100644
--- a/src/libgit2/win32/w32_util.c
+++ b/src/util/win32/w32_util.c
diff --git a/src/libgit2/win32/w32_util.h b/src/util/win32/w32_util.h
index 1321d30e6..519663720 100644
--- a/src/libgit2/win32/w32_util.h
+++ b/src/util/win32/w32_util.h
@@ -8,7 +8,7 @@
 #ifndef INCLUDE_win32_w32_util_h__
 #define INCLUDE_win32_w32_util_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include "utf-conv.h"
 #include "posix.h"
diff --git a/src/libgit2/win32/win32-compat.h b/src/util/win32/win32-compat.h
index dee40a438..dee40a438 100644
--- a/src/libgit2/win32/win32-compat.h
+++ b/src/util/win32/win32-compat.h
diff --git a/src/libgit2/zstream.c b/src/util/zstream.c
index cb8b125ed..cb8b125ed 100644
--- a/src/libgit2/zstream.c
+++ b/src/util/zstream.c
diff --git a/src/libgit2/zstream.h b/src/util/zstream.h
index 3f8b1c72f..d78b11291 100644
--- a/src/libgit2/zstream.h
+++ b/src/util/zstream.h
@@ -7,7 +7,7 @@
 #ifndef INCLUDE_zstream_h__
 #define INCLUDE_zstream_h__
 
-#include "common.h"
+#include "git2_util.h"
 
 #include <zlib.h>