cc: do not expand function-like macros for non-function invocations

It is a bit of a annoyance that kenc will try to expand
function like macros on any symbol with the same name
and then complain when it doesnt see the '(' in the
invocation.

test case below:

void
foo(int)
{
}

struct Bar
{
	int	baz;	/* <- should not conflict */
};

void
main(void)
{
	baz(123);
}

1 files changed, 1 insertions, 1 deletions

diff --git a/sys/src/cmd/va/a.h b/sys/src/cmd/va/a.h
index 63bec8038..1c2b7c223 100644
--- a/sys/src/cmd/va/a.h
+++ b/sys/src/cmd/va/a.h
@@ -136,7 +136,7 @@ Sym*	getsym(void);
 void	domacro(void);
 void	macund(void);
 void	macdef(void);
-void	macexpand(Sym*, char*, int);
+int	macexpand(Sym*, char*, int);
 void	macinc(void);
 void	maclin(void);
 void	macprag(void);