error about & at top level until it is safe

R=ken
OCL=17241
CL=17241
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index eb88067..92dc126 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -468,6 +468,8 @@
 
 EXTERN	int	exporting;
 
+EXTERN	int	func;
+
 /*
  *	y.tab.c
  */