7142167: MAC: _get_previous_fp broken on bsd with llvm-gcc

Summary: LLVM-GCC (__llvm__) should use the same _get_previous_fp implementation as __clang__ (as is the case for os::current_stack_pointer).
Reviewed-by: twisti, never, dcubed

src/os_cpu/bsd_x86/vm/os_bsd_x86.cpp

 /*
- * Copyright (c) 1999, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -362,7 +362,7 @@ frame os::get_sender_for_C_frame(frame* fr) {
 }
 
 intptr_t* _get_previous_fp() {
-#if defined(SPARC_WORKS) || defined(__clang__)
+#if defined(SPARC_WORKS) || defined(__clang__) || defined(__llvm__)
   register intptr_t **ebp;
   __asm__("mov %%"SPELL_REG_FP", %0":"=r"(ebp));
 #else