feat: add cross-compiler for Windows

.gitignore

@@ -52,7 +52,7 @@ Mkfile.old
 dkms.conf
 
 # Build directory
-build/
+build*/
 
 # CCLS cache
 .ccls-cache/

Makefile

@@ -22,3 +22,9 @@ compile:
 debug:
 	@echo "[Makefile] Running debug target..."
 	@./build/sdl2_debug
+
+# Compile for windows
+compile-windows:
+	@echo "[Makefile] Compile for Windows..."
+	@cmake -G "Ninja" -DCMAKE_TOOLCHAIN_FILE=`pwd`/toolchain/win-mingw.cmake -B build-win -S src
+	@cmake --build build-win

src/CMakeLists.txt

@@ -10,6 +10,9 @@ project(ComputerGraphics
 # TODO: potentially add bundled SDL2 version
 #   in an `external` directory (maybe submodules)
 find_package(SDL2 REQUIRED CONFIG REQUIRED COMPONENTS SDL2)
+if (WIN32)
+    find_package(SDL2 REQUIRED CONFIG COMPONENTS SDL2main)
+endif (WIN32)
 
 # Add subdirectories
 add_subdirectory(core)
@@ -20,7 +23,10 @@ add_executable(sdl2_debug WIN32 debug.c)
 add_executable(render WIN32 render.c)
 
 # Obtain libraries
-set(SHARED_LIBRARIES SDL2::SDL2)
+if (WIN32)
+    set(SHARED_LIBRARIES mingw32 SDL2::SDL2main)
+endif (WIN32)
+set(SHARED_LIBRARIES ${SHARED_LIBRARIES} SDL2::SDL2)
 find_library(math m)
 if(math)
     set(SHARED_LIBRARIES ${SHARED_LIBRARIES} ${math})

toolchain/win-mingw.cmake

@@ -0,0 +1,17 @@
+# the name of the target operating system
+set(CMAKE_SYSTEM_NAME WIN32)
+
+# which compilers to use for C and C++
+set(CMAKE_C_COMPILER x86_64-w64-mingw32-gcc)
+set(CMAKE_CXX_COMPILER x86_64-w64-mingw32-g++)
+
+# where is the target environment located
+set(CMAKE_FIND_ROOT_PATH /usr/x86_64-w64-mingw32/)
+
+# adjust the default behavior of the FIND_XXX() commands:
+# search programs in the host environment
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+# search headers and libraries in the target environment
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)