Replace thread_local with a new macro BASE_THREAD_LOCAL. Set this macro to...

Replace thread_local with a new macro BASE_THREAD_LOCAL. Set this macro to selectively disable thread_local on platforms that don't support it correctly, e.g., Xcode < 8, and gcc < 4.8.3. Progress now uses BASE_THREAD_LOCAL instead of thread_local.

Progress/ProgressNode.cc

@@ -57,7 +57,7 @@ void Context::exit_node()
   actv_node_ = prnt == nullptr ? &phny_root_ : prnt;
 }
 
-thread_local Context cntx;
+BASE_THREAD_LOCAL Context cntx;
 
 /// Node implementation
 Node::~Node() 

Progress/ProgressNode.hh

@@ -4,14 +4,10 @@
 #define BASE_PROGRESS_NODE_HH_INCLUDED
 
 #ifdef PROGRESS_ON
-namespace Progress {
 
-#if defined(__apple_build_version__)
-// work around the lack of thread_local support in XCode 7
-#if !__has_feature(cxx_thread_local)
-#define thread_local // disable thread_local
-#endif//!__has_feature(cxx_thread_local)
-#endif//defined(__apple_build_version__)
+#include <Base/Utils/Thread.hh>
+
+namespace Progress {
    
 //! Progress tick counter type
 typedef unsigned long long TickNumber;
@@ -134,7 +130,7 @@ private:
 };
 
 //! the current thread Progress context
-extern thread_local Context cntx;
+extern BASE_THREAD_LOCAL Context cntx;
 
 /*! 
 Enable (or disable) the Context::abort() processing, use to enable abort() 

Utils/CMakeLists.txt

@@ -5,6 +5,7 @@ set(my_headers
    ${CMAKE_CURRENT_SOURCE_DIR}/IOutputStream.hh
    ${CMAKE_CURRENT_SOURCE_DIR}/OStringStream.hh
    ${CMAKE_CURRENT_SOURCE_DIR}/StopWatch.hh
+   ${CMAKE_CURRENT_SOURCE_DIR}/Thread.hh
    ${CMAKE_CURRENT_SOURCE_DIR}/ThrowError.hh
    PARENT_SCOPE
 )

Utils/Thread.hh

+// (C) Copyright 2017 by Autodesk, Inc.
+
+#ifndef BASE_THREAD_HH_INCLUDED
+#define BASE_THREAD_HH_INCLUDED
+
+// System specific thread support
+
+#if defined(__apple_build_version__)
+// work around the lack of thread_local support in XCode 7
+#if !__has_feature(cxx_thread_local)
+#define BASE_THREAD_LOCAL_BROKEN 
+#endif//!__has_feature(cxx_thread_local)
+#endif//defined(__apple_build_version__)
+
+// TODO: move these macros to a more suitable location
+#define GCC_VERSION(MAJOR, MINOR, PATCH) \
+  (MAJOR * 10000 +  MINOR * 100 + PATCH)
+#define GCC_VERSION_CURRENT\
+  GCC_VERSION(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__)
+
+#if defined(__GNUC__) && GCC_VERSION_CURRENT < GCC_VERSION(4, 8, 3)
+// there is a thread_local linker bug prior to gcc-4.8.3
+// see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55800
+#define BASE_THREAD_LOCAL_BROKEN 
+#endif//__GNUC__
+
+#ifdef BASE_THREAD_LOCAL_BROKEN // if broken do not use thread_local
+#define BASE_THREAD_LOCAL
+#else// BASE_THREAD_LOCAL_BROKEN
+#define BASE_THREAD_LOCAL thread_local
+#endif// BASE_THREAD_LOCAL_BROKEN
+
+#endif//BASE_THREAD_HH_INCLUDED