I'm getting this when trying to build on Mac OS X 10.6: CC nsterm.o nsterm.m: In function '-[EmacsView toggleFullScreen:]': nsterm.m:7058: error: 'NSWindowWillEnterFullScreenNotification' undeclared (first use in this function) nsterm.m:7058: error: (Each undeclared identifier is reported only once nsterm.m:7058: error: for each function it appears in.) nsterm.m:7066: error: 'NSWindowDidEnterFullScreenNotification' undeclared (first use in this function) nsterm.m:7098: error: 'NSWindowWillExitFullScreenNotification' undeclared (first use in this function) nsterm.m:7104: error: 'NSWindowDidExitFullScreenNotification' undeclared (first use in this function) make[1]: *** [nsterm.o] Error 1 make: *** [src] Error 2 make failed Looks like this commit is the culprit: commit 35cd51814507987b916c4b4e0a7b45e09e454341 Author: David Reitter Date: Sat Nov 7 20:43:29 2015 -0500 Provide NS notification objects where required to eliminate warnings * nsterm.m (windowDidResize:, toggleFullScreen:): Call notification functions with notification objects as per delegate APIs. NSWindow.h says: APPKIT_EXTERN NSString * const NSWindowWillEnterFullScreenNotification NS_AVAILABLE_MAC(10_7); APPKIT_EXTERN NSString * const NSWindowDidEnterFullScreenNotification NS_AVAILABLE_MAC(10_7); APPKIT_EXTERN NSString * const NSWindowWillExitFullScreenNotification NS_AVAILABLE_MAC(10_7); APPKIT_EXTERN NSString * const NSWindowDidExitFullScreenNotification NS_AVAILABLE_MAC(10_7); We could fix this by wrapping NSWindow*FullScreenNotification with preprocessor guards. On the other hand, that's getting awfully bulky for creating a bunch of NSNotifications that aren't ever used (follow the function calls). Perhaps we can fix the warning a different way? -David