gc: more accurate error description

R=ken2
CC=golang-dev
https://golang.org/cl/1284041

src/cmd/gc/go.errors

@@ -45,10 +45,10 @@ static struct {
 	"var declaration not allowed in for initializer",
 
 	% loadsys package imports LVAR LNAME '[' ']' LNAME '{'
-	"var declaration missing = before initial value",
+	"unexpected { at end of statement",
 
 	% loadsys package imports LFUNC LNAME '(' ')' '{' LVAR LNAME '[' ']' LNAME '{'
-	"var declaration missing = before initial value",
+	"unexpected { at end of statement",
 	
 	% loadsys package imports LFUNC LNAME '(' ')' '{' LDEFER LNAME ';'
 	"argument to go/defer must be function call",

test/syntax/vareq.go

@@ -7,4 +7,4 @@
 package main
 
 func main() {
-	var x map[string]string{"a":"b"}		// ERROR "var declaration missing ="
+	var x map[string]string{"a":"b"}		// ERROR "unexpected { at end of statement"

test/syntax/vareq1.go

@@ -6,5 +6,5 @@
 
 package main
 
-var x map[string]string{"a":"b"}		// ERROR "var declaration missing ="
+var x map[string]string{"a":"b"}		// ERROR "unexpected { at end of statement"