Add utility classes for dealing with Windows

Most for GLFW and SDL only

core/sys/darwin/Foundation/NSWindow.odin

@@ -0,0 +1,41 @@
+package objc_Foundation
+
+import NS "core:sys/darwin/Foundation"
+
+@(objc_class="CALayer")
+Layer :: struct { using _: NS.Object }
+
+@(objc_class="NSResponder")
+Responder :: struct {using _: Object}
+
+@(objc_class="NSView")
+View :: struct {using _: Responder}
+
+@(objc_class="NSWindow")
+Window :: struct {using _: Responder}
+
+@(objc_type=Window, objc_name="contentView")
+Window_contentView :: proc(self: ^Window) -> ^View {
+	return msgSend(^View, self, "contentView")
+}
+
+@(objc_type=View, objc_name="layer")
+View_layer :: proc(self: ^View) -> ^Layer {
+	return msgSend(^Layer, self, "layer")
+}
+
+@(objc_type=View, objc_name="setLayer")
+View_setLayer :: proc(self: ^View, layer: ^Layer) {
+	msgSend(nil, self, "setLayer:", layer)
+}
+
+
+@(objc_type=View, objc_name="wantsLayer")
+View_wantsLayer :: proc(self: ^View) -> BOOL {
+	return msgSend(BOOL, self, "wantsLayer")
+}
+
+@(objc_type=View, objc_name="setWantsLayer")
+View_setWantsLayer :: proc(self: ^View, wantsLayer: BOOL) {
+	msgSend(nil, self, "setWantsLayer:", wantsLayer)
+}