Disable recvmsg on MacOS for now as a test

src/public/tier0/platform_sockets.h

@@ -110,7 +110,6 @@ typedef char SteamNetworkingErrMsg[ 1024 ];
 		return errno;
 	}
 
-	#define PlatformSupportsRecvMsg() true
 
 	#ifdef __APPLE__
 		#define USE_POLL
@@ -119,6 +118,11 @@ typedef char SteamNetworkingErrMsg[ 1024 ];
 		// it should work, I would appreciate the help.
 		#define PlatformSupportsRecvTOS() false
 
+		// Some weird problem with tests on MacOS.  We only need recvmsg
+		// to receive the TOS, which doesn't work.  So let's just turn it off
+		// and see it fixes the tests.
+		#define PlatformSupportsRecvMsg() false
+
 	#else
 		#define USE_EPOLL
 		#include <sys/epoll.h>
@@ -145,6 +149,8 @@ typedef char SteamNetworkingErrMsg[ 1024 ];
 		// FIXME - should we try to use eventfd() here
 		// instead of a socket pair?
 
+		#define PlatformSupportsRecvMsg() true
+
 	#endif
 #else
 	#error "How do?"