Fix the name of thread safety macros.

src/google/protobuf/stubs/atomicops.h

@@ -54,7 +54,7 @@
 #define GOOGLE_PROTOBUF_ATOMICOPS_H_
 
 // Don't include this file for people not concerned about thread safety.
-#ifndef GOOGLE_PROTOBUF_NO_THREADSAFETY
+#ifndef GOOGLE_PROTOBUF_NO_THREAD_SAFETY
 
 #include <google/protobuf/stubs/platform_macros.h>
 
@@ -197,6 +197,6 @@ GOOGLE_PROTOBUF_ATOMICOPS_ERROR
 
 #undef GOOGLE_PROTOBUF_ATOMICOPS_ERROR
 
-#endif  // GOOGLE_PROTOBUF_NO_THREADSAFETY
+#endif  // GOOGLE_PROTOBUF_NO_THREAD_SAFETY
 
 #endif  // GOOGLE_PROTOBUF_ATOMICOPS_H_

src/google/protobuf/stubs/atomicops_internals_x86_msvc.cc

@@ -32,7 +32,7 @@
 // Therefore we move the code depending on windows.h to this separate cc file.
 
 // Don't compile this file for people not concerned about thread safety.
-#ifndef GOOGLE_PROTOBUF_NO_THREADSAFETY
+#ifndef GOOGLE_PROTOBUF_NO_THREAD_SAFETY
 
 #include <google/protobuf/stubs/atomicops.h>
 
@@ -109,4 +109,4 @@ Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
 }  // namespace google
 
 #endif  // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_X86_MSVC_H_
-#endif  // GOOGLE_PROTOBUF_NO_THREADSAFETY
+#endif  // GOOGLE_PROTOBUF_NO_THREAD_SAFETY