Use strings.Contains in src/cmd/...

R=r
CC=golang-dev, r2, rsc
https://golang.org/cl/2819041

src/cmd/cgo/gcc.go

@@ -223,14 +223,14 @@ func (p *Package) guessKinds(f *File) []*Name {
 		switch {
 		default:
 			continue
-		case strings.Index(line, ": useless type name in empty declaration") >= 0:
+		case strings.Contains(line, ": useless type name in empty declaration"):
 			what = "type"
 			isConst[i] = false
-		case strings.Index(line, ": statement with no effect") >= 0:
+		case strings.Contains(line, ": statement with no effect"):
 			what = "not-type" // const or func or var
-		case strings.Index(line, "undeclared") >= 0:
+		case strings.Contains(line, "undeclared"):
 			error(noPos, "%s", strings.TrimSpace(line[colon+1:]))
-		case strings.Index(line, "is not an integer constant") >= 0:
+		case strings.Contains(line, "is not an integer constant"):
 			isConst[i] = false
 			continue
 		}

src/cmd/goinstall/download.go

@@ -38,7 +38,7 @@ var launchpad = regexp.MustCompile(`^(launchpad\.net/([a-z0-9A-Z_.\-]+(/[a-z0-9A
 
 // download checks out or updates pkg from the remote server.
 func download(pkg string) (string, os.Error) {
-	if strings.Index(pkg, "..") >= 0 {
+	if strings.Contains(pkg, "..") {
 		return "", os.ErrorString("invalid path (contains ..)")
 	}
 	if m := bitbucket.FindStringSubmatch(pkg); m != nil {