Fix compiling with PThread support on Windows... Again...

Summary: I was bad and didn't follow through on my previous test plan, and so didn't check that it completely fixed the issue, instead only fixing one of the two problems. This fixes the other one.

Reviewed By: yfeldblum

Differential Revision: D4988408

fbshipit-source-id: 44389bc67bcb7d6db984075f3600948460fa8c5a

folly/ThreadName.cpp

@@ -90,6 +90,10 @@ bool setThreadName(std::thread::id tid, StringPiece name) {
 
 #if FOLLY_HAVE_PTHREAD
 bool setThreadName(pthread_t pid, StringPiece name) {
+#if _WIN32
+  // Not currently supported on Windows.
+  return false;
+#else
   static_assert(
       std::is_same<pthread_t, std::thread::native_handle_type>::value,
       "This assumes that the native handle type is pthread_t");
@@ -103,6 +107,7 @@ bool setThreadName(pthread_t pid, StringPiece name) {
   std::thread::id id;
   std::memcpy(&id, &pid, sizeof(id));
   return setThreadName(id, name);
+#endif
 }
 #endif