Fix lock assertion violation in GC_try_to_collect_inner on OS X

(fix of commit b7b1004)

Issue #583 (bdwgc).

This happens only in the multi-threaded collector with assertions on
and malloc redirection if GC_enable_incremental() is called.

* include/private/gc_priv.h [MPROTECT_VDB && DARWIN]: Include pthread.h
(wrapped into EXTERN_C_END/BEGIN).
* include/private/gc_priv.h [MPROTECT_VDB && DARWIN && THREADS]
(GC_inner_pthread_create): Declare (as GC_INNER function).
* include/private/gc_priv.h [MPROTECT_VDB && DARWIN && !THREADS]
(GC_inner_pthread_create): Define as macro (redirecting to
pthread_create).
* os_dep.c [MPROTECT_VDB && DARWIN]: Do not include pthread.h.
* os_dep.c [MPROTECT_VDB && DARWIN] (pthread_create): Do not undefine.
* os_dep.c [MPROTECT_VDB && DARWIN] (GC_dirty_init): Call
GC_inner_pthread_create() instead of pthread_create().
* pthread_support.c [MPROTECT_VDB && DARWIN] (GC_inner_pthread_create):
Define function (call INIT_REAL_SYMS() and REAL_FUNC(pthread_create)).

include/private/gc_priv.h

@@ -2581,6 +2581,19 @@ GC_EXTERN GC_bool GC_print_back_height;
 #   endif
 # endif /* CAN_HANDLE_FORK */
 
+# if defined(MPROTECT_VDB) && defined(DARWIN)
+    EXTERN_C_END
+#   include <pthread.h>
+    EXTERN_C_BEGIN
+#   ifdef THREADS
+      GC_INNER int GC_inner_pthread_create(pthread_t *t,
+                                GC_PTHREAD_CREATE_CONST pthread_attr_t *a,
+                                void *(*fn)(void *), void *arg);
+#   else
+#     define GC_inner_pthread_create pthread_create
+#   endif
+# endif /* MPROTECT_VDB && DARWIN */
+
   GC_INNER GC_bool GC_dirty_init(void);
                 /* Returns true if dirty bits are maintained (otherwise */
                 /* it is OK to be called again if the client invokes    */

os_dep.c

@@ -4352,7 +4352,6 @@ GC_INNER GC_bool GC_dirty_init(void)
 #include <mach/mach_error.h>
 #include <mach/exception.h>
 #include <mach/task.h>
-#include <pthread.h>
 
 EXTERN_C_BEGIN
 
@@ -4746,9 +4745,8 @@ GC_INNER GC_bool GC_dirty_init(void)
   if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0)
     ABORT("pthread_attr_setdetachedstate failed");
 
-# undef pthread_create
-  /* This will call the real pthread function, not our wrapper */
-  if (pthread_create(&thread, &attr, GC_mprotect_thread, NULL) != 0)
+  /* This will call the real pthread function, not our wrapper. */
+  if (GC_inner_pthread_create(&thread, &attr, GC_mprotect_thread, NULL) != 0)
     ABORT("pthread_create failed");
   (void)pthread_attr_destroy(&attr);
 

pthread_support.c

@@ -261,6 +261,16 @@
 # define INIT_REAL_SYMS() (void)0
 #endif /* GC_WIN32_THREADS */
 
+#if defined(MPROTECT_VDB) && defined(DARWIN)
+  GC_INNER int GC_inner_pthread_create(pthread_t *t,
+                                GC_PTHREAD_CREATE_CONST pthread_attr_t *a,
+                                void *(*fn)(void *), void *arg)
+  {
+    INIT_REAL_SYMS();
+    return REAL_FUNC(pthread_create)(t, a, fn, arg);
+  }
+#endif
+
 #ifndef GC_ALWAYS_MULTITHREADED
   GC_INNER GC_bool GC_need_to_lock = FALSE;
 #endif