export large constants

R=r
DELTA=37  (31 added, 4 deleted, 2 changed)
OCL=14089
CL=14089
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index af50d48..16efdc9 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -487,6 +487,7 @@
 void	mpatoflt(Mpflt *a, char *s);
 void	mpmovefltfix(Mpint *a, Mpflt *b);
 void	mpmovefixflt(Mpflt *a, Mpint *b);
+int	Bconv(Fmt*);
 
 /*
  *	mparith2.c