Make file system watcher compile on Mac OS 106, and add a runtime-call to test if the system suppor…

runtime/bin/file_system_watcher_macos.cc

Index: runtime/bin/file_system_watcher_macos.cc
diff --git a/runtime/bin/file_system_watcher_macos.cc b/runtime/bin/file_system_watcher_macos.cc
index c06572f30e8e066507b2b3228e50341c8c1f24d7..b694bfddfd174478dc3ae1f024cd434c65d04e57 100644
--- a/runtime/bin/file_system_watcher_macos.cc
+++ b/runtime/bin/file_system_watcher_macos.cc
@@ -18,6 +18,26 @@
 #include "bin/thread.h"
 
 
+#ifndef MAC_OS_X_VERSION_10_7
+enum {
+  kFSEventStreamCreateFlagFileEvents = 0x00000010
+};
+enum {
+  kFSEventStreamEventFlagItemCreated = 0x00000100,
+  kFSEventStreamEventFlagItemRemoved = 0x00000200,
+  kFSEventStreamEventFlagItemInodeMetaMod = 0x00000400,
+  kFSEventStreamEventFlagItemRenamed = 0x00000800,
+  kFSEventStreamEventFlagItemModified = 0x00001000,
+  kFSEventStreamEventFlagItemFinderInfoMod = 0x00002000,
+  kFSEventStreamEventFlagItemChangeOwner = 0x00004000,
+  kFSEventStreamEventFlagItemXattrMod = 0x00008000,
+  kFSEventStreamEventFlagItemIsFile = 0x00010000,
+  kFSEventStreamEventFlagItemIsDir = 0x00020000,
+  kFSEventStreamEventFlagItemIsSymlink = 0x00040000
+};
+#endif
+
+
 namespace dart {
 namespace bin {
 
@@ -191,6 +211,12 @@ class FSEventsWatcher {
 };
 
 
+#define kCFCoreFoundationVersionNumber10_7      635.00
+bool FileSystemWatcher::IsSupported() {
+  return kCFCoreFoundationVersionNumber >= kCFCoreFoundationVersionNumber10_7;
+}
+
+
 intptr_t FileSystemWatcher::WatchPath(const char* path,
                                       int events,
                                       bool recursive) {