Replace conditional extern 'C' blocks begin/end with EXTERN_C_BEGIN/END

(code refactoring)

Issue #206 (bdwgc).

Note: EXTERN_C_BEGIN and EXTERN_C_END are not available in the GC
public headers.

* include/private/darwin_stop_world.h: Replace the conditional
extern "C" block begin/end with EXTERN_C_BEGIN and EXTERN_C_END,
respectively.
* include/private/dbg_mlc.h: Likewise.
* include/private/gc_hdrs.h: Likewise.
* include/private/gc_locks.h: Likewise.
* include/private/gc_pmark.h: Likewise.
* include/private/gc_priv.h: Likewise.
* include/private/gcconfig.h: Likewise.
* include/private/pthread_stop_world.h: Likewise.
* include/private/pthread_support.h: Likewise.
* include/private/specific.h: Likewise.
* include/private/thread_local_alloc.h: Likewise.
* os_dep.c [MPROTECT_VDB && DARWIN]: Likewise.
* tests/test.c [GC_AMIGA_FASTALLOC && AMIGA]: Likewise.
* include/private/gcconfig.h (EXTERN_C_BEGIN, EXTERN_C_END): Define
macro.

1 files changed, 2 insertions, 6 deletions

diff --git a/os_dep.c b/os_dep.c
index f7369ac2..1cd4e890 100644
--- a/os_dep.c
+++ b/os_dep.c
@@ -3914,9 +3914,7 @@ GC_INNER void GC_remove_protection(struct hblk *h, word nblocks,
 #include <mach/task.h>
 #include <pthread.h>
 
-#ifdef __cplusplus
-  extern "C" {
-#endif
+EXTERN_C_BEGIN
 
 /* Some of the following prototypes are missing in any header, although */
 /* they are documented.  Some are in mach/exc.h file.                   */
@@ -3961,9 +3959,7 @@ catch_exception_raise_state_identity(mach_port_name_t exception_port,
                 int flavor, thread_state_t old_state, int old_stateCnt,
                 thread_state_t new_state, int new_stateCnt);
 
-#ifdef __cplusplus
-  } /* extern "C" */
-#endif
+EXTERN_C_END
 
 /* These should never be called, but just in case...  */
 GC_API_OSCALL kern_return_t