change build system to CMake and use SDL3 for everything

libs/SDL3/cmake/test/main_gui.c

@@ -0,0 +1,24 @@
+#include <SDL3/SDL.h>
+#include <SDL3/SDL_main.h>
+
+int main(int argc, char *argv[])
+{
+    SDL_Window *window = NULL;
+    SDL_Surface *screenSurface = NULL;
+    if (!SDL_Init(SDL_INIT_VIDEO)) {
+        SDL_Log("Could not initialize SDL: %s", SDL_GetError());
+        return 1;
+    }
+    window = SDL_CreateWindow("Hello SDL", 640, 480, 0);
+    if (!window) {
+        SDL_Log("could not create window: %s", SDL_GetError());
+        return 1;
+    }
+    screenSurface = SDL_GetWindowSurface(window);
+    SDL_FillSurfaceRect(screenSurface, NULL, SDL_MapSurfaceRGB(screenSurface, 0xff, 0xff, 0xff));
+    SDL_UpdateWindowSurface(window);
+    SDL_Delay(100);
+    SDL_DestroyWindow(window);
+    SDL_Quit();
+    return 0;
+}