Partial revert of rev58110

There's one thing we didn't foresee from the beginning,
which is apparently TLS is only available in OSX starting
from version 10.7, and we still do support of 10.6.

After recent Brecht's changes about locked viewport
while initializing BI render this TLS is not needed
in trunk anymore. So reverting this chunk of base
iteration to use static variable. But leaving all the
other static variables warped into context still, it
should help a bit in the future refactor.

Real fix would be to have some kind of graph context
evaluation structure which would be passing to update
routines (which will solve threaded mballs update) and
making depsgraph responsible for getting a motherball.
But this is all for GSoC project.

source/blender/blenkernel/intern/scene.c

@@ -748,7 +748,7 @@ void BKE_scene_unlink(Main *bmain, Scene *sce, Scene *newsce)
  */
 int BKE_scene_base_iter_next(SceneBaseIter *iter, Scene **scene, int val, Base **base, Object **ob)
 {
-	static ThreadVariable int in_next_object = 0;
+	static int in_next_object = 0;
 	int run_again = 1;
 	
 	/* init */

source/blender/blenlib/BLI_threads.h

@@ -182,13 +182,6 @@ int BLI_thread_queue_size(ThreadQueue *queue);
 void BLI_thread_queue_wait_finish(ThreadQueue *queue);
 void BLI_thread_queue_nowait(ThreadQueue *queue);
 
-/* Thread Local Storage */
-#ifdef _MSC_VER
-#  define ThreadVariable  __declspec(thread)
-#else
-#  define ThreadVariable  __thread
-#endif
-
 #ifdef __cplusplus
 }
 #endif