Fix "jst" GDB macro

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/669383002

Cr-Commit-Position: refs/heads/master@{#24881}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24881 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

tools/gdbinit

@@ -40,7 +40,7 @@ end
 
 # Print JavaScript stack trace.
 define jst
-print v8::internal::Isolate::Current()->PrintStack(stdout)
+print v8::internal::Isolate::Current()->PrintStack((FILE*) stdout)
 end
 document jst
 Print the current JavaScript stack trace