cmd/cgo: map C unsigned char back to _Ctype_uchar in error messages

Fixes #13635.

Change-Id: Icab4a45567f435f002a8f6c85db9538acf054a70
Reviewed-on: https://go-review.googlesource.com/17863
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

misc/cgo/errors/issue13635.go

+// Copyright 2015 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.
+
+// issue 13635: used to output error about C.unsignedchar.
+// This test tests all such types.
+
+package pkg
+
+import "C"
+
+func main() {
+	var (
+		_ C.uchar         = "uc"  // ERROR HERE
+		_ C.schar         = "sc"  // ERROR HERE
+		_ C.ushort        = "us"  // ERROR HERE
+		_ C.uint          = "ui"  // ERROR HERE
+		_ C.ulong         = "ul"  // ERROR HERE
+		_ C.longlong      = "ll"  // ERROR HERE
+		_ C.ulonglong     = "ull" // ERROR HERE
+		_ C.complexfloat  = "cf"  // ERROR HERE
+		_ C.complexdouble = "cd"  // ERROR HERE
+	)
+}

misc/cgo/errors/test.bash

@@ -16,7 +16,7 @@ check() {
 
 expect() {
 	file=$1
-	error=$2
+	shift
 	if go build $file >errs 2>&1; then
 		echo 1>&2 misc/cgo/errors/test.bash: BUG: expected cgo to fail but it succeeded
 		exit 1
@@ -25,11 +25,13 @@ expect() {
 		echo 1>&2 misc/cgo/errors/test.bash: BUG: expected error output but saw none
 		exit 1
 	fi
+	for error; do
 		if ! fgrep $error errs >/dev/null 2>&1; then
 			echo 1>&2 misc/cgo/errors/test.bash: BUG: expected error output to contain \"$error\" but saw:
 			cat 1>&2 errs
 			exit 1
 		fi
+	done
 }
 
 check err1.go
@@ -41,6 +43,7 @@ check issue11097a.go
 check issue11097b.go
 expect issue13129.go C.ushort
 check issue13423.go
+expect issue13635.go C.uchar C.schar C.ushort C.uint C.ulong C.longlong C.ulonglong C.complexfloat C.complexdouble
 
 if ! go run ptr.go; then
 	exit 1

src/cmd/cgo/gcc.go

@@ -1319,6 +1319,7 @@ var dwarfToName = map[string]string{
 	"long long int":          "longlong",
 	"long long unsigned int": "ulonglong",
 	"signed char":            "schar",
+	"unsigned char":          "uchar",
 }
 
 const signedDelta = 64