message: gpuvis_trace_utils: Prefer C++11 thread_local vs. __thread
  If using a >= C++11 compatible compiler, use thread_local instead of
  __thread. This fixes a compilation error with Clang that doesn't provide
  GCC's __thread.
diff: #ifdef __cplusplus
  #define GPUVIS_EXTERN extern "C"
  + #if __cplusplus>=201103L
  + #define THREAD_LOCAL thread_local
  + #else
  + #define THREAD_LOCAL __thread
  + #endif
  #else
  #define GPUVIS_EXTERN extern
  #endif
  @@ -351,7 +356,7 @@ static void flush_hot_func_calls()
  GPUVIS_EXTERN void gpuvis_count_hot_func_calls_internal_( const char *func )
  {
  - static __thread pid_t s_tid = gpuvis_gettid();
  + static THREAD_LOCAL pid_t s_tid = gpuvis_gettid();
  uint64_t t0 = gpuvis_gettime_u64();
  auto &x = g_hotfuncs[ s_tid ];
  