do not insert implicit "return;" in empty function body

R=ken
OCL=32239
CL=32239

src/cmd/gc/dcl.c

@@ -636,7 +636,7 @@ funclit1(Node *ntype, NodeList *body)
 	n->nname = f;
 	n->type = ft;
 	if(body == nil)
-		body = list1(nod(ORETURN, N, N));
+		body = list1(nod(OEMPTY, N, N));
 	n->nbody = body;
 	compile(n);
 	funcdepth--;

src/cmd/gc/go.y

@@ -1196,7 +1196,7 @@ fnbody:
 	{
 		$$ = $2;
 		if($$ == nil)
-			$$ = list1(nod(ORETURN, N, N));
+			$$ = list1(nod(OEMPTY, N, N));
 		yyoptsemi(0);
 	}
 

test/fixedbugs/bug043.go

@@ -18,6 +18,6 @@ func g (x int) float ;  // BUG this doesn't
 func g (x int) float { return 0.0 }
 
 func h (x int) (u int, v int) ;  // BUG this doesn't
-func h (x int) (u int, v int) {}
+func h (x int) (u int, v int) { return; }
 
 func main() {}

test/fixedbugs/bug080.go

@@ -7,9 +7,11 @@
 package main	
  	
 func f1() (x int, y float) {
+	return;
 }
 
 func f2   (x int, y float) {
+	return;
 }
 
 func main() {

test/fixedbugs/bug171.go

+// errchk $G $D/$F.go
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func f() int { }	// ERROR "return"
+func g() (foo int) { }	// ERROR "return"