Unconditionally disable thread_local in hazard pointer when on mobile

Summary:
Sometimes the compiler lies to us and says it supports thread_local when it is not always fully implemented.

Unconditionally disable this when `FOLLY_MOBILE` is set

Reviewed By: yfeldblum

Differential Revision: D6875230

fbshipit-source-id: 051f79eac78da03973bad9090b6577393b88998b

folly/experimental/hazptr/hazptr-impl.h

@@ -30,9 +30,9 @@
 
 #ifndef HAZPTR_TC
 
-// If we are on an IOS device or simulator and don't have thread_local support
-// then do not use thread caching
-#if FOLLY_MOBILE && defined(__APPLE__) && !FOLLY_HAS_FEATURE(cxx_thread_local)
+// If we are on an IOS device or simulator then do not use thread caching
+// Performance is potentially suboptimal without thread local support
+#if FOLLY_MOBILE && defined(__APPLE__)
 #define HAZPTR_TC false
 #else
 #define HAZPTR_TC true
@@ -44,9 +44,9 @@
 #endif
 
 #ifndef HAZPTR_PRIV
-// If we are on an IOS device or simulator and don't have thread_local support
-// then do not use private
-#if FOLLY_MOBILE && defined(__APPLE__) && !FOLLY_HAS_FEATURE(cxx_thread_local)
+// If we are on an IOS device or simulator then do not use thread caching
+// Performance is potentially suboptimal without thread local support
+#if FOLLY_MOBILE && defined(__APPLE__)
 #define HAZPTR_PRIV false
 #else
 #define HAZPTR_PRIV true