The fix for RT-39138 introduced these compilation errors on Mac when running with XCode 4.5 and gcc (which is our production compiler for FX 8u builds).

$ gradle sdk
...
:fxpackager:compileMacLibrary
/Users/kcr/javafx/8u-kcr/jfx/rt/modules/fxpackager/src/main/native/library/common/MacPlatform.mm: In member function 'virtual TString MacPlatform::GetAppDataDirectory()':
/Users/kcr/javafx/8u-kcr/jfx/rt/modules/fxpackager/src/main/native/library/common/MacPlatform.mm:161: warning: 'NSArray' may not respond to '-firstObject'
/Users/kcr/javafx/8u-kcr/jfx/rt/modules/fxpackager/src/main/native/library/common/MacPlatform.mm:161: warning: (Messages without a matching method signature
/Users/kcr/javafx/8u-kcr/jfx/rt/modules/fxpackager/src/main/native/library/common/MacPlatform.mm:161: warning: will be assumed to return 'id' and accept
/Users/kcr/javafx/8u-kcr/jfx/rt/modules/fxpackager/src/main/native/library/common/MacPlatform.mm:161: warning: '...' as arguments.)
/Users/kcr/javafx/8u-kcr/jfx/rt/modules/fxpackager/src/main/native/library/common/MacPlatform.mm: In member function 'bool UserDefaults::ReadPreferences(NSDictionary*, std::list<std::basic_string<char, std::char_traits<char>, std::allocator
<char> >, std::allocator<std::basic_string<char, std::char_traits<char>, std::allocator<char> > > >, TOrderedMap&)':
/Users/kcr/javafx/8u-kcr/jfx/rt/modules/fxpackager/src/main/native/library/common/MacPlatform.mm:380: error: invalid types 'NSDictionary*[NSString*]' for array subscript
:fxpackager:compileMacLibrary FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':fxpackager:compileMacLibrary'.
> Could not call NativeCompileTask.compile() on task ':fxpackager:compileMacLibrary'