Add windows cross-compile capability

CMakeLists.txt

@@ -18,6 +18,12 @@ set_source_files_properties(${OUTPUT_NAME} PROPERTIES
   GENERATED TRUE)
 add_custom_target(bittool_lang DEPENDS "${OUTPUT_NAME}")
 
+if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
+  set(PLATFORM_FILES "win32/resources.rc")
+else()
+  set(PLATFORM_FILES "")
+endif()
+
 add_executable(bittool
     main.cpp
     DroidSansFallback.cpp
@@ -29,6 +35,7 @@ add_executable(bittool
     imgui/imgui_widgets.cpp
     imgui/backends/imgui_impl_sdl.cpp
     imgui/backends/imgui_impl_opengl3.cpp
+    ${PLATFORM_FILES}
 )
 
 set_property(TARGET bittool PROPERTY CXX_STANDARD 14)
@@ -41,6 +48,11 @@ if(${CMAKE_SYSTEM_NAME} MATCHES "Linux")
     install(FILES unix/bittool.svg DESTINATION share/icons/hicolor/scalable/apps)
 endif()
 
+if(${CMAKE_SYSTEM_NAME} MATCHES "Windows" AND ${CMAKE_CXX_COMPILER_ID} MATCHES "GNU")
+    set(IS_MINGW_BUILD "Y")
+    target_link_options(bittool PUBLIC -static-libgcc -static-libstdc++ -static)
+endif()
+
 find_package(Freetype)
 
 if(Freetype_FOUND)
@@ -65,10 +77,14 @@ else()
 	find_package(SDL2 REQUIRED)
 	if (TARGET SDL2::SDL2)
 		message(STATUS "bittool: using TARGET SDL2::SDL2")
-		target_link_libraries(bittool PRIVATE SDL2::SDL2)
+		if(${IS_MINGW_BUILD} STREQUAL "Y")
+          target_link_libraries(bittool PRIVATE SDL2::SDL2main SDL2::SDL2-static)
+		else()
+          target_link_libraries(bittool PRIVATE SDL2::SDL2main SDL2::SDL2)
+        endif()
 	elseif (TARGET SDL2)
 		message(STATUS "bittool: using TARGET SDL2")
-		target_link_libraries(bittool PRIVATE SDL2)
+		target_link_libraries(bittool PRIVATE SDL2main SDL2)
 	else()
 		message(STATUS "bittool: no TARGET SDL2::SDL2, or SDL2, using variables")
 		target_include_directories(testapp PRIVATE "$<BUILD_INTERFACE:${SDL2_INCLUDE_DIRS}>")

win32/mingw-w64-x86_64.cmake

@@ -0,0 +1,21 @@
+
+# Build with x86_64-w64-mingw32 on Ubuntu
+
+set(CMAKE_SYSTEM_NAME Windows)
+set(TOOLCHAIN_PREFIX x86_64-w64-mingw32)
+
+# cross compilers to use for C, C++ and Fortran
+set(CMAKE_C_COMPILER ${TOOLCHAIN_PREFIX}-gcc)
+set(CMAKE_CXX_COMPILER ${TOOLCHAIN_PREFIX}-g++)
+set(CMAKE_Fortran_COMPILER ${TOOLCHAIN_PREFIX}-gfortran)
+set(CMAKE_RC_COMPILER ${TOOLCHAIN_PREFIX}-windres)
+
+# target environment on the build host system
+set(CMAKE_FIND_ROOT_PATH /usr/${TOOLCHAIN_PREFIX})
+
+set(SDL2_DIR /usr/x86_64-w64-mingw32/sys-root/mingw/lib/cmake/SDL2)
+
+# modify default behavior of FIND_XXX() commands
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY) 

win32/resources.rc

@@ -0,0 +1 @@
+IDI_ICON1               ICON        DISCARDABLE            "bittool.ico"