[asan] more support for powerpc, patch by Peter Bergner

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@168356 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/sanitizer_common/sanitizer_stacktrace.h b/lib/sanitizer_common/sanitizer_stacktrace.h
index b823a7e..fe2dcf0 100644
--- a/lib/sanitizer_common/sanitizer_stacktrace.h
+++ b/lib/sanitizer_common/sanitizer_stacktrace.h
@@ -45,6 +45,8 @@
 
   void FastUnwindStack(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom);
 
+  void PopStackFrames(uptr count);
+
   static uptr GetCurrentPc();
 
   static uptr CompressStack(StackTrace *stack,