Does not build for macOS under Xcode 12.2

[pkclsoft]

Parse Issue Group
.../GCMMultiplayer.h:103:165: Expected ':'
.../GCMMultiplayer.m:9:9: In file included from .../GCMMultiplayer.m:9:
User-Defined Issue Group
.../GCMMultiplayer.m:187:6: GCMMultiplayer::sendMatchData not implemented

ARC Semantic Issue Group
.../GCMMultiplayer.m:66:37: No visible @interface for 'NSViewController' declares the selector 'presentViewController:animated:completion:'
.../GCMMultiplayer.m:85:37: No visible @interface for 'NSViewController' declares the selector 'presentViewController:animated:completion:'
.../GCMMultiplayer.m:224:37: No visible @interface for 'NSViewController' declares the selector 'dismissViewControllerAnimated:completion:'
.../GCMMultiplayer.m:229:37: No visible @interface for 'NSViewController' declares the selector 'dismissViewControllerAnimated:completion:'
.../GCMMultiplayer.m:235:37: No visible @interface for 'NSViewController' declares the selector 'dismissViewControllerAnimated:completion:'

Semantic Issue Group
.../GCMMultiplayer.m:215:1: Implementing unavailable method
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.0.sdk/System/Library/Frameworks/GameKit.framework/Headers/GKMatchmaker.h:110:1: Method 'player:didRequestMatchWithPlayers:' declared here

.../GCMMultiplayer.m:252:1: Implementing deprecated method
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.0.sdk/System/Library/Frameworks/GameKit.framework/Headers/GKMatch.h:79:1: Method 'match:didReceiveData:fromPlayer:' declared here

.../GCMMultiplayer.m:260:1: Implementing deprecated method
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.0.sdk/System/Library/Frameworks/GameKit.framework/Headers/GKMatch.h:80:1: Method 'match:player:didChangeState:' declared here