runtime: fix windows build

#ifdef'ed out code wasn't updated for argp change.

TBR=iant
CC=golang-codereviews
https://golang.org/cl/139040043

diff --git a/src/pkg/runtime/traceback_x86.c b/src/pkg/runtime/traceback_x86.c
index ac451240e21fc40bba85bc8b39081e9f2799ac3e..169407ac81a8a171d38fc67e764f5fc1e5dc48e1 100644 (file)
--- a/src/pkg/runtime/traceback_x86.c
+++ b/src/pkg/runtime/traceback_x86.c
@@ -132,7 +132,7 @@ runtime·gentraceback(uintptr pc0, uintptr sp0, uintptr lr0, G *gp, int32 skip,
                        // Invoke callback so that stack copier sees an uncopyable frame.
                        if(callback != nil) {
                                frame.continpc = frame.pc;
-                               frame.argp = nil;
+                               frame.argp = 0;
                                frame.arglen = 0;
                                if(!callback(&frame, v))
                                        return n;