[glibmm] Move thread_local check into a GLIBMM_CXX_* macro, like other checks.

[Murray Cumming <murrayc src gnome org>]

commit cdfdb3d916ee9b03465b2fe2f85b9953d14d944d
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Mar 28 21:51:57 2016 +0200

    Move thread_local check into a GLIBMM_CXX_* macro, like other checks.
    
    Bug #759791

 build/cxx.m4                    |   21 +++++++++++++++++++++
 configure.ac                    |    7 +------
 glib/glibmm/dispatcher.cc       |   14 +++++++-------
 glib/glibmm/exceptionhandler.cc |   10 +++++-----
 4 files changed, 34 insertions(+), 18 deletions(-)
---
diff --git a/build/cxx.m4 b/build/cxx.m4
index 22d2435..58e4f85 100644
--- a/build/cxx.m4
+++ b/build/cxx.m4
@@ -236,3 +236,24 @@ AS_VAR_IF([glibmm_cv_cxx_can_use_namespaces_inside_externc], ['yes'],
           [AC_DEFINE([GLIBMM_CAN_USE_NAMESPACES_INSIDE_EXTERNC], [1],
                      [Define if the compiler honors namespaces inside extern "C" blocks.])])[]dnl
 ])
+
+## GLIBMM_CXX_CAN_USE_THREAD_LOCAL
+##
+## Check for thread_local support
+##
+AC_DEFUN([GLIBMM_CXX_CAN_USE_THREAD_LOCAL],
+[dnl
+AC_CACHE_CHECK(
+  [whether the thread_local keyword is supported],
+  [glibmm_cv_cxx_can_use_thread_local],
+  [AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+[[
+thread_local int i=0;
+]], [])],
+    [glibmm_cv_cxx_can_use_thread_local=yes],
+    [glibmm_cv_cxx_can_use_thread_local=no])])
+
+AS_VAR_IF([glibmm_cv_cxx_can_use_thread_local], ['yes'],
+          [AC_DEFINE([GLIBMM_CAN_USE_THREAD_LOCAL], [1],
+                     [Define if the thread_local keyword is supported.])])[]dnl
+])
diff --git a/configure.ac b/configure.ac
index 70f61ce..535348b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -104,14 +104,9 @@ GLIBMM_CXX_CAN_USE_DYNAMIC_CAST_IN_UNUSED_TEMPLATE_WITHOUT_DEFINITION
 GLIBMM_CXX_CAN_ASSIGN_NON_EXTERN_C_FUNCTIONS_TO_EXTERN_C_CALLBACKS
 GLIBMM_CXX_CAN_USE_NAMESPACES_INSIDE_EXTERNC
 GLIBMM_CXX_ALLOWS_STATIC_INLINE_NPOS
+GLIBMM_CXX_CAN_USE_THREAD_LOCAL
 GLIBMM_C_STD_TIME_T_IS_NOT_INT32
 
-# check for thread_local support
-AC_MSG_CHECKING([whether the thread_local keyword is supported])
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([thread_local int i=0;], [])],
-       AC_DEFINE([GLIBMM_THREAD_LOCAL_ENABLED], [1], [thread_local keyword is available])
-       AC_MSG_RESULT([yes]) , AC_MSG_RESULT([no]))
-
 MM_ARG_ENABLE_DOCUMENTATION
 MM_ARG_WITH_TAGFILE_DOC([libstdc++.tag], [mm-common-libstdc++])
 MM_ARG_WITH_TAGFILE_DOC([libsigc++-2.0.tag], [sigc++-2.0])
diff --git a/glib/glibmm/dispatcher.cc b/glib/glibmm/dispatcher.cc
index 9ee3b0c..e21914a 100644
--- a/glib/glibmm/dispatcher.cc
+++ b/glib/glibmm/dispatcher.cc
@@ -15,7 +15,7 @@
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#ifndef GLIBMM_THREAD_LOCAL_ENABLED
+#ifndef GLIBMM_CAN_USE_THREAD_LOCAL
 #include <glibmm/threads.h>
 #endif
 
@@ -147,7 +147,7 @@ protected:
   explicit DispatchNotifier(const Glib::RefPtr<MainContext>& context);
 
 private:
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
   static thread_local DispatchNotifier* thread_specific_instance_;
 #else
   static Glib::Threads::Private<DispatchNotifier> thread_specific_instance_;
@@ -175,7 +175,7 @@ private:
 
 // static
 
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
 thread_local DispatchNotifier* DispatchNotifier::thread_specific_instance_ = nullptr;
 #else
 Glib::Threads::Private<DispatchNotifier> DispatchNotifier::thread_specific_instance_;
@@ -282,7 +282,7 @@ DispatchNotifier*
 DispatchNotifier::reference_instance(
   const Glib::RefPtr<MainContext>& context, const Dispatcher* dispatcher)
 {
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
   DispatchNotifier* instance = thread_specific_instance_;
 #else
   DispatchNotifier* instance = thread_specific_instance_.get();
@@ -291,7 +291,7 @@ DispatchNotifier::reference_instance(
   if (!instance)
   {
     instance = new DispatchNotifier(context);
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
     thread_specific_instance_ = instance;
 #else
     thread_specific_instance_.replace(instance);
@@ -323,7 +323,7 @@ DispatchNotifier::reference_instance(
 void
 DispatchNotifier::unreference_instance(DispatchNotifier* notifier, const Dispatcher* dispatcher)
 {
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
   DispatchNotifier* const instance = thread_specific_instance_;
 #else
   DispatchNotifier* const instance = thread_specific_instance_.get();
@@ -344,7 +344,7 @@ DispatchNotifier::unreference_instance(DispatchNotifier* notifier, const Dispatc
   {
     g_return_if_fail(instance->ref_count_ == 0); // could be < 0 if messed up
 
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
     delete thread_specific_instance_;
     thread_specific_instance_ = nullptr;
 #else
diff --git a/glib/glibmm/exceptionhandler.cc b/glib/glibmm/exceptionhandler.cc
index 7311bbe..60809db 100644
--- a/glib/glibmm/exceptionhandler.cc
+++ b/glib/glibmm/exceptionhandler.cc
@@ -19,7 +19,7 @@
  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#ifndef GLIBMM_THREAD_LOCAL_ENABLED
+#ifndef GLIBMM_CAN_USE_THREAD_LOCAL
 #include <glibmm/threads.h>
 #endif
 #include <glibmmconfig.h>
@@ -36,7 +36,7 @@ typedef sigc::signal<void> HandlerList;
 
 // Each thread has its own list of exception handlers
 // to avoid thread synchronization problems.
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
 static thread_local HandlerList* thread_specific_handler_list = nullptr;
 #else
 static Glib::Threads::Private<HandlerList> thread_specific_handler_list;
@@ -92,7 +92,7 @@ namespace Glib
 sigc::connection
 add_exception_handler(const sigc::slot<void>& slot)
 {
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
   HandlerList* handler_list = thread_specific_handler_list;
 #else
   HandlerList* handler_list = thread_specific_handler_list.get();
@@ -101,7 +101,7 @@ add_exception_handler(const sigc::slot<void>& slot)
   if (!handler_list)
   {
     handler_list = new HandlerList();
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
     thread_specific_handler_list = handler_list;
 #else
     thread_specific_handler_list.set(handler_list);
@@ -129,7 +129,7 @@ exception_handlers_invoke() noexcept
   // handled.  If there are no more handlers in the list and the exception
   // is still unhandled, call glibmm_unexpected_exception().
 
-#ifdef GLIBMM_THREAD_LOCAL_ENABLED
+#ifdef GLIBMM_CAN_USE_THREAD_LOCAL
   if (HandlerList* const handler_list = thread_specific_handler_list)
 #else
   if(HandlerList *const handler_list = thread_specific_handler_list.get())