Embed the SDL2 libraries into vendor:sdl2

vendor/sdl2/sdl_timer.odin

@@ -0,0 +1,25 @@
+package sdl2
+
+import "core:c"
+
+when ODIN_OS == "windows" do foreign import lib "SDL2.lib"
+when ODIN_OS == "linux"   do foreign import lib "system:SDL2"
+when ODIN_OS == "darwin"  do foreign import lib "system:SDL2"
+when ODIN_OS == "freebsd" do foreign import lib "system:SDL2"
+
+TimerCallback :: proc "c" (interval: u32, param: rawptr) -> u32;
+TimerID :: distinct c.int;
+
+TICKS_PASSED :: #force_inline proc "c" (A, B: u32) -> bool {
+	return bool(i32(B) - i32(A) <= 0);
+}
+
+@(default_calling_convention="c", link_prefix="SDL_")
+foreign lib {
+	GetTicks                :: proc() -> u32 ---
+	GetPerformanceCounter   :: proc() -> u64 ---
+	GetPerformanceFrequency :: proc() -> u64 ---
+	Delay                   :: proc(ms: u32) ---
+	AddTimer                :: proc(interval: u32, callback: TimerCallback, param: rawptr) -> TimerID ---
+	RemoveTimer             :: proc(id: TimerID) -> bool ---
+}