include(CheckIncludeFile)
set(include_files
    linux/fs.h
    pwd.h
    sys/clonefile.h
    sys/ioctl.h
    sys/mman.h
    sys/time.h
    sys/wait.h
    sys/file.h
    syslog.h
    termios.h
    dirent.h
    strings.h
    unistd.h
    utime.h
    sys/utime.h
    varargs.h)
foreach(include_file IN ITEMS ${include_files})
  string(TOUPPER ${include_file} include_var)
  string(REGEX REPLACE "[/.]" "_" include_var ${include_var})
  set(include_var HAVE_${include_var})
  check_include_file(${include_file} ${include_var})
endforeach()

include(CheckFunctionExists)
set(functions
    asctime_r
    getopt_long
    getpwuid
    posix_fallocate
    realpath
    setenv
    strndup
    syslog
    unsetenv
    utimensat
    utimes
)
foreach(func IN ITEMS ${functions})
  string(TOUPPER ${func} func_var)
  set(func_var HAVE_${func_var})
  check_function_exists(${func} ${func_var})
endforeach()

include(CheckStructHasMember)
check_struct_has_member("struct stat" st_atim sys/stat.h
                        HAVE_STRUCT_STAT_ST_ATIM LANGUAGE CXX)
check_struct_has_member("struct stat" st_ctim sys/stat.h
                        HAVE_STRUCT_STAT_ST_CTIM LANGUAGE CXX)
check_struct_has_member("struct stat" st_mtim sys/stat.h
                        HAVE_STRUCT_STAT_ST_MTIM LANGUAGE CXX)
check_struct_has_member("struct stat" st_atimespec sys/stat.h
                        HAVE_STRUCT_STAT_ST_ATIMESPEC LANGUAGE CXX)
check_struct_has_member("struct stat" st_ctimespec sys/stat.h
                        HAVE_STRUCT_STAT_ST_CTIMESPEC LANGUAGE CXX)
check_struct_has_member("struct stat" st_mtimespec sys/stat.h
                        HAVE_STRUCT_STAT_ST_MTIMESPEC LANGUAGE CXX)
check_struct_has_member("struct statfs" f_fstypename sys/mount.h
                        HAVE_STRUCT_STATFS_F_FSTYPENAME LANGUAGE CXX)

include(CheckCXXSourceCompiles)
check_cxx_source_compiles(
  [=[
    #include <immintrin.h>
    #ifndef _MSC_VER // MSVC does not need explicit enabling of AVX2.
    void func() __attribute__((target("avx2")));
    #endif
    void func() { _mm256_abs_epi8(_mm256_set1_epi32(42)); }
    int main()
    {
      func();
      return 0;
    }
  ]=]
  HAVE_AVX2)

if(WIN32)
  set(_WIN32_WINNT 0x0600)
endif()

if(CMAKE_SYSTEM MATCHES "Darwin")
  set(_DARWIN_C_SOURCE 1)
endif()

# alias
set(MTR_ENABLED "${ENABLE_TRACING}")

if(HAVE_SYS_MMAN_H
   AND (HAVE_STRUCT_STAT_ST_MTIM OR HAVE_STRUCT_STAT_ST_MTIMESPEC)
   AND (HAVE_LINUX_FS_H OR HAVE_STRUCT_STATFS_F_FSTYPENAME))
  set(INODE_CACHE_SUPPORTED 1)
endif()

# Escape backslashes in SYSCONFDIR for C.
file(TO_NATIVE_PATH "${CMAKE_INSTALL_FULL_SYSCONFDIR}" CONFIG_SYSCONFDIR_C_ESCAPED)
string(REPLACE "\\" "\\\\" CONFIG_SYSCONFDIR_C_ESCAPED "${CONFIG_SYSCONFDIR_C_ESCAPED}")

configure_file(${CMAKE_SOURCE_DIR}/cmake/config.h.in
               ${CMAKE_BINARY_DIR}/config.h @ONLY)