devdraw: add Cursor2 support on macOS 10.14 Mojave

This replaces the pixel-art scaling algorithm used for upscaling before.
The results were not crisp enough to serve as everyday cursors.

src/cmd/devdraw/cocoa-screen.m

@@ -1410,8 +1410,10 @@ kicklabel0(char *label) {
 }
 
 void
-setcursor(Cursor *c)
+setcursor(Cursor *c, Cursor2 *c2)
 {
+	USED(c2);
+
 	/*
 	 * No cursor change unless in main thread.
 	 */
@@ -1658,3 +1660,9 @@ setprocname(const char *s)
   if(err != noErr)
     fprint(2, "Call to set process name failed\n");
 }
+
+void
+resizewindow(Rectangle r)
+{
+	USED(r);
+}