Embed the SDL2 libraries into vendor:sdl2

vendor/sdl2/sdl_touch.odin

@@ -0,0 +1,37 @@
+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"
+
+TouchID  :: distinct i64;
+FingerID :: distinct i64;
+
+TouchDeviceType :: enum c.int {
+	INVALID = -1,
+	DIRECT,            /* touch screen with window-relative coordinates */
+	INDIRECT_ABSOLUTE, /* trackpad with absolute device coordinates */
+	INDIRECT_RELATIVE, /* trackpad with screen cursor-relative coordinates */
+}
+
+Finger :: struct {
+    id: FingerID,
+    x:        f32,
+    y:        f32,
+    pressure: f32,
+}
+
+TOUCH_MOUSEID  :: ~u32(0);
+MOUSE_TOUCH_ID :: TouchID(-1);
+
+@(default_calling_convention="c", link_prefix="SDL_")
+foreign lib {
+	GetNumTouchDevices :: proc() -> c.int ---
+	GetTouchDevice     :: proc(index: c.int) -> TouchID ---
+	GetTouchDeviceType :: proc(touchID: TouchID) -> TouchDeviceType ---
+	GetNumTouchFingers :: proc(touchID: TouchID) -> c.int ---
+	GetTouchFinger     :: proc(touchID: TouchID, index: c.int) -> ^Finger ---
+}