Quoted from https://github.com/EricssonResearch/openwebrtc/issues/297 (i.e. this is not me writing about the issue but I wanted to report it so it didn't get lost):

My build always fail with 'gst-plugins-good-1.0'. I'm done with the bootstrap. I'm now running the full build for the host system; in my case it's Mac OSX Yosemite. I was able to build it on Mac before using the old build system.

I'm getting flooded with errors so I'm pasting here the last few lines since they seem to be repeating anyway:

command: ./cerbero-uninstalled -c config/osx-x86-64.cbc package openwebrtc

```
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/CoreData.h:36:0,
                 from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/Cocoa.framework/Headers/Cocoa.h:14,
                 from cocoawindow.m:30:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:53:12: error: expected identifier before ')' token
 @property () BOOL usesStoreSpecificMigrationManager NS_AVAILABLE(10_7,  5_0);
            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:59:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSMappingModel *mappingModel;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:60:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSManagedObjectModel *sourceModel;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:61:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSManagedObjectModel *destinationModel;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:64:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSManagedObjectContext *sourceContext;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:65:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSManagedObjectContext *destinationContext;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:82:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSEntityMapping *currentEntityMapping;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSMigrationManager.h:88:29: error: unknown property attribute before ')' token
 @property (nonatomic, strong) NSDictionary *userInfo;
                             ^
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/CoreData.h:39:0,
                 from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/Cocoa.framework/Headers/Cocoa.h:14,
                 from cocoawindow.m:30:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSIncrementalStoreNode.h:46:39: error: unknown property attribute before ')' token
 @property (nonatomic, readonly, strong) NSManagedObjectID *objectID;
                                       ^
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/CoreData.h:42:0,
                 from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/Cocoa.framework/Headers/Cocoa.h:14,
                 from cocoawindow.m:30:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:40:18: error: unknown property attribute before ',' token
 @property (strong, readonly) NSManagedObjectContext* managedObjectContext;
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:40:1: note: 'assign' can be unsafe for Objective-C objects; please state explicitly if you need it
 @property (strong, readonly) NSManagedObjectContext* managedObjectContext;
 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:41:18: error: unknown property attribute before ',' token
 @property (strong, readonly) NSError* operationError;
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:41:1: note: 'assign' can be unsafe for Objective-C objects; please state explicitly if you need it
 @property (strong, readonly) NSError* operationError;
 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:42:18: error: unknown property attribute before ',' token
 @property (strong, readonly) NSProgress* progress;
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:42:1: note: 'assign' can be unsafe for Objective-C objects; please state explicitly if you need it
 @property (strong, readonly) NSProgress* progress;
 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:58:18: error: unknown property attribute before ',' token
 @property (strong, readonly) id result;
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:58:1: note: 'assign' can be unsafe for Objective-C objects; please state explicitly if you need it
 @property (strong, readonly) id result;
 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:72:18: error: unknown property attribute before ',' token
 @property (strong, readonly) NSAsynchronousFetchRequest* fetchRequest;
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:72:1: note: 'assign' can be unsafe for Objective-C objects; please state explicitly if you need it
 @property (strong, readonly) NSAsynchronousFetchRequest* fetchRequest;
 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:73:18: error: unknown property attribute before ',' token
 @property (strong, readonly) NSArray* finalResult;
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSPersistentStoreResult.h:73:1: note: 'assign' can be unsafe for Objective-C objects; please state explicitly if you need it
 @property (strong, readonly) NSArray* finalResult;
 ^
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/CoreData.h:43:0,
                 from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/Cocoa.framework/Headers/Cocoa.h:14,
                 from cocoawindow.m:30:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSSaveChangesRequest.h:28:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSSet *insertedObjects;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSSaveChangesRequest.h:30:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSSet *updatedObjects;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSSaveChangesRequest.h:32:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSSet *deletedObjects;
                            ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSSaveChangesRequest.h:34:28: error: unknown property attribute before ')' token
 @property (readonly, strong) NSSet *lockedObjects;
                            ^
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/CoreData.h:44:0,
                 from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/Cocoa.framework/Headers/Cocoa.h:14,
                 from cocoawindow.m:30:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSBatchUpdateRequest.h:41:18: error: unknown property attribute before ',' token
 @property (strong, readonly) NSEntityDescription *entity;
                  ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSBatchUpdateRequest.h:41:1: note: 'assign' can be unsafe for Objective-C objects; please state explicitly if you need it
 @property (strong, readonly) NSEntityDescription *entity;
 ^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/CoreData.framework/Headers/NSBatchUpdateRequest.h:42:18: error: unknown property attribute before ')' token
 @property (strong) NSPredicate *predicate;
                  ^
osxvideosink.m: In function '-[GstOSXVideoSinkObject showFrame:]':
osxvideosink.m:865:11: warning: variable 'data' set but not used [-Wunused-but-set-variable]
   guint8 *data, *readp, *writep;
           ^
make[3]: *** [libgstosxvideosink_la-osxvideosink.lo] Error 1
make[3]: *** Waiting for unfinished jobs....
cocoawindow.m: In function '-[GstOSXVideoSinkWindow initWithContentNSRect:styleMask:backing:defer:screen:]':
cocoawindow.m:301:5: warning: 'GstOSXVideoSinkWindow' may not respond to '-setContentView:' [enabled by default]
     [self setContentView:gstview];
     ^
cocoawindow.m:301:5: warning: (Messages without a matching method signature [enabled by default]
cocoawindow.m:301:5: warning: will be assumed to return 'id' and accept [enabled by default]
cocoawindow.m:301:5: warning: '...' as arguments.) [enabled by default]
cocoawindow.m: In function '-[GstGLView initWithFrame:]':
cocoawindow.m:356:4: warning: 'GstGLView' may not respond to '-openGLContext' [enabled by default]
    actualContext = [self openGLContext];
    ^
cocoawindow.m: In function '-[GstGLView setFullScreen:]':
cocoawindow.m:623:5: warning: 'GstGLView' may not respond to '-openGLContext' [enabled by default]
     actualContext = [self openGLContext];
     ^
make[3]: *** [libgstosxvideosink_la-cocoawindow.lo] Error 1
make[2]: *** [osxvideo] Error 2
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
Running command 'make -j4'

Recipe 'gst-plugins-good-1.0' failed at the build step 'compile'
```

Does it have something to do with me using the beta version of Xcode? I can't seem to find any document related to the build requirements.

Thanks in advance.