[compiler-rt] Introduce MACOS_VERSION_UNKNOWN_NEWER for OS X versions above 10.10

[kubamracek]

Summary

We recently had a broken version check because an newer OS X version is treated as MACOS_VERSION_UNKNOWN which is less than all the defined values. Let's have a separate enum value for unknown but newer versions, so the ">=" and "<=" version checks still work even in upcoming OS X releases.

[kubamracek]

ping

[samsonov]

LGTM

[kubamracek]

Landed in r224315 with a modification to use IsDigit() instead of the multiple case labels.

projects/compiler-rt/lib/sanitizer_common/sanitizer_mac.h

enum MacosVersion {
   MACOS_VERSION_UNINITIALIZED = 0,
   MACOS_VERSION_UNKNOWN,
   MACOS_VERSION_LEOPARD,
   MACOS_VERSION_SNOW_LEOPARD,
   MACOS_VERSION_LION,
   MACOS_VERSION_MOUNTAIN_LION,
   MACOS_VERSION_MAVERICKS,
   MACOS_VERSION_YOSEMITE,
+  MACOS_VERSION_UNKNOWN_NEWER
 };
 
 MacosVersion GetMacosVersion();
 
 }  // namespace __sanitizer
 
 #endif  // SANITIZER_MAC
 #endif  // SANITIZER_MAC_H

projects/compiler-rt/lib/sanitizer_common/sanitizer_mac.cc

     case '9': return MACOS_VERSION_LEOPARD;
     case '1': {
       switch (version[1]) {
         case '0': return MACOS_VERSION_SNOW_LEOPARD;
         case '1': return MACOS_VERSION_LION;
         case '2': return MACOS_VERSION_MOUNTAIN_LION;
         case '3': return MACOS_VERSION_MAVERICKS;
         case '4': return MACOS_VERSION_YOSEMITE;
+        case '5':
+        case '6':
+        case '7':
+        case '8':
+        case '9': return MACOS_VERSION_UNKNOWN_NEWER;
         default: return MACOS_VERSION_UNKNOWN;
       }
     }
     default: return MACOS_VERSION_UNKNOWN;
   }
 }
 
 MacosVersion GetMacosVersion() {