Implement CMake, mostly for cross-compiling from non-Windows

.gitignore

@@ -5,4 +5,5 @@
 *.pdb
 *.user
 Debug/
-Release/
+Release/
+build/

CMakeLists.txt

@@ -0,0 +1,69 @@
+# Can only cross-compile on non-Windows for obvious reasons, so enforce.
+if(CMAKE_HOST_UNIX)
+	set(CMAKE_SYSTEM_NAME "Windows")
+	set(CMAKE_SYSTEM_VERSION "10.0")
+	set(CMAKE_FIND_ROOT_PATH /usr/i686-w64-mingw32)
+
+	# Use host binaries but target libraries and headers.
+	set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+
+	set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+	set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+endif()
+
+set(CMAKE_SYSTEM_PROCESSOR "x86")
+
+cmake_minimum_required(VERSION 3.22)
+project(SCGL LANGUAGES C CXX)
+
+if(NOT CMAKE_HOST_WIN32 AND NOT CMAKE_CROSSCOMPILING)
+	message(FATAL_ERROR "SCGL targets SimCity 4, a 32-bit Windows application, and must be cross-compiled.")
+endif()
+
+if(NOT CMAKE_SIZEOF_VOID_P EQUAL 4)
+	message(FATAL_ERROR "You're using a compiler that generates 64-bit code. SCGL must be 32-bit.")
+endif()
+
+add_library(SCGL SHARED
+            scgl/cGDriver.cpp
+            scgl/cGDriversCOMDirector.cpp
+            scgl/cGDriver_Info.cpp
+            scgl/cGDriver_Init.cpp
+            scgl/cGDriver_Textures.cpp
+            scgl/cGDriver_Unknown.cpp
+            scgl/cGDriver_Viewport.cpp
+            scgl/ext/cGDriver_BufferRegions.cpp
+            scgl/ext/cGDriver_Lighting.cpp
+            scgl/ext/cGDriver_Snapshot.cpp
+            scgl/ext/cGDriver_VertexBuffers.cpp
+            scgl/GLStateManager.cpp
+            scgl/GLSupport.cpp
+            scgl/GLTextureUnit.cpp
+            scgl/VertexFormatUtils.cpp
+            vendor/framework/src/cRZCOMDllDirector.cpp
+            vendor/framework/src/cRZRefCount.cpp
+)
+
+set_target_properties(SCGL PROPERTIES PREFIX "")
+
+target_include_directories(SCGL PRIVATE "${CMAKE_SOURCE_DIR}/vendor/framework/include;${CMAKE_SOURCE_DIR}/scgl;${CMAKE_SOURCE_DIR}/scgl/ext")
+
+# Flags for debug builds.
+target_compile_options(SCGL PRIVATE
+                       $<$<AND:$<CXX_COMPILER_ID:MSVC>,$<CONFIG:Debug>>:/W3 /utf-8 /MP>
+                       $<$<AND:$<OR:$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:GNU>>,$<CONFIG:Debug>>:-Wall -fpermissive>
+)
+
+# For release
+target_compile_options(SCGL PRIVATE
+                       $<$<AND:$<CXX_COMPILER_ID:MSVC>,$<CONFIG:Release>>:/W3 /utf-8 /Gw /Zc:threadSafeInit- /O2>
+                       $<$<AND:$<OR:$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:GNU>>,$<CONFIG:Release>>:-Wall -fpermissive -O3 -flto>
+)
+
+# Definitions
+target_compile_definitions(SCGL PRIVATE
+                           $<$<AND:$<OR:$<CXX_COMPILER_ID:GNU>,$<CXX_COMPILER_ID:Clang>>,$<CONFIG:Debug>>:__FUNCSIG__=__PRETTY_FUNCTION__>
+)
+
+# Should come with MinGW
+target_link_libraries(SCGL opengl32.lib)

scgl/GLSupport.h

@@ -1,7 +1,7 @@
 #pragma once
 #define WIN32_LEAN_AND_MEAN
-#include <Windows.h>
-#include <GL/GL.h>
+#include <windows.h>
+#include <GL/gl.h>
 
 // ---------------------- Begin GLext subset ----------------------
 #ifndef APIENTRY