From 08984077ea5f2933b3f25a678a1f2be717ae12d0 Mon Sep 17 00:00:00 2001
From: Zachary Lund <admin@computerquip.com>
Date: Fri, 14 Feb 2020 19:27:59 -0600
Subject: add flag to support standalone executables

---
 CMakeLists.txt       | 10 ++++++++++
 colm/CMakeLists.txt  |  8 ++++++++
 ragel/CMakeLists.txt | 17 ++++++++++++++---
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cb910b74..56400bd1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,6 +22,16 @@ set(${PROJECT_NAME}_MAKE_INSTALL ON CACHE BOOL
 set(${PROJECT_NAME}_BUILD_EXAMPLES OFF CACHE BOOL
 	"Set to ON to build examples (default is OFF)")
 
+# Determine stdlib link flags
+if (WIN32)
+	set(DEFAULT_BUILD_STANDALONE ON)
+else()
+	set(DEFAULT_BUILD_STANDALONE OFF)
+endif()
+
+set(BUILD_STANDALONE ${DEFAULT_BUILD_STANDALONE}
+	CACHE BOOL "Set to ON to make the executables as standalone as possible.")
+
 # Check type size
 include(CheckTypeSize)
 check_type_size("int" SIZEOF_INT)
diff --git a/colm/CMakeLists.txt b/colm/CMakeLists.txt
index fb84401d..3d855523 100644
--- a/colm/CMakeLists.txt
+++ b/colm/CMakeLists.txt
@@ -143,6 +143,14 @@ add_executable(colm
 	"${CMAKE_CURRENT_BINARY_DIR}/gen/parse3.c"
 	"${CMAKE_CURRENT_BINARY_DIR}/gen/if3.cc")
 
+if(BUILD_STANDALONE)
+	if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+		target_link_libraries(colm -static)
+	else()
+		message(FATAL_ERROR "Unsupported toolset for standalone build.")
+	endif()
+endif()
+
 target_link_libraries(colm libprog libcolm)
 
 set_property(TARGET colm APPEND PROPERTY
diff --git a/ragel/CMakeLists.txt b/ragel/CMakeLists.txt
index 448141fe..3e797981 100644
--- a/ragel/CMakeLists.txt
+++ b/ragel/CMakeLists.txt
@@ -27,7 +27,6 @@ set(RUNTIME_HDR
 include(GNUInstallDirs)
 
 # libfsm
-
 add_library(libfsm
 	buffer.h codegen.h
 	actloop.h actexp.h
@@ -59,13 +58,25 @@ set_target_properties(libfsm PROPERTIES
 	OUTPUT_NAME fsm)
 
 # libragel
-
 add_library(libragel
 	# dist
 	parsedata.h parsetree.h inputdata.h pcheck.h reducer.h rlscan.h load.h
 	parsetree.cc longest.cc parsedata.cc inputdata.cc load.cc reducer.cc)
 
-target_link_libraries(libragel colm::libcolm)
+if(BUILD_STANDALONE)
+	# libragel acts as an intermediate library so we can apply
+	# flags we want to apply to all ragel targets to libragel
+	# and they'll automatically propogate. This is a best effort
+	# to get `-static` placed sooner in the link line where it
+	# matters at least.
+	if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+		target_link_libraries(libragel PUBLIC -static)
+	else()
+		message(FATAL_ERROR "Unsupported toolset for standalone build.")
+	endif()
+endif()
+
+target_link_libraries(libragel PRIVATE colm::libcolm)
 
 target_include_directories(libragel
 	PUBLIC
-- 
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