Fix typo in Mac GetCurrentThreadId

BUG=none
TBR=svenpanne@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/642223003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24512 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/base/platform/platform-posix.cc

@@ -254,7 +254,7 @@ int OS::GetCurrentProcessId() {
 
 int OS::GetCurrentThreadId() {
 #if V8_OS_MACOSX
-  return static_cast<int>(pthread_mac_thread_np(pthread_self()));
+  return static_cast<int>(pthread_mach_thread_np(pthread_self()));
 #elif V8_OS_LINUX
   return static_cast<int>(syscall(__NR_gettid));
 #elif V8_OS_ANDROID