gc: better printing of named constants, func literals

R=ken2
CC=golang-dev
https://golang.org/cl/2121045

src/cmd/gc/print.c

@@ -119,6 +119,10 @@ exprfmt(Fmt *f, Node *n, int prec)
 		break;
 
 	case OLITERAL:
+		if(n->sym != S) {
+			fmtprint(f, "%S", n->sym);
+			break;
+		}
 		switch(n->val.ctype) {
 		default:
 			goto bad;
@@ -259,6 +263,10 @@ exprfmt(Fmt *f, Node *n, int prec)
 		exprfmt(f, n->left, 0);
 		break;
 
+	case OCLOSURE:
+		fmtprint(f, "func literal");
+		break;
+
 	case OCOMPLIT:
 		fmtprint(f, "composite literal");
 		break;