Resolved the NSWindowDelegate issue and added an explicit NSApplicationDelegate specifier just to be safe; thanks to Zorg__ in irc.freenode.net/#macdev for explaining (it's an issue with NSApp specifically).

redo/uitask_darwin.m

@@ -4,7 +4,7 @@
 #import "_cgo_export.h"
 #import <Cocoa/Cocoa.h>
 
-@interface appDelegateClass : NSObject
+@interface appDelegateClass : NSObject <NSApplicationDelegate>
 @end
 
 @implementation appDelegateClass

redo/window_darwin.m

@@ -6,7 +6,6 @@
 
 #define toNSWindow(x) ((NSWindow *) (x))
 
-// TODO why do I need the explicit interface specification?
 @interface goWindowDelegate : NSObject <NSWindowDelegate> {
 @public
 	void *gowin;