cmd/go: do not print GCC environment variables on Plan 9

R=seed, rminnich, r, minux.ma
CC=golang-dev
https://golang.org/cl/7397059

src/cmd/go/env.go

@@ -34,12 +34,10 @@ func mkEnv() []envVar {
  b.init()
 
  env := []envVar{
- {"CC", b.gccCmd(".")[0]},
  {"GOARCH", goarch},
  {"GOBIN", gobin},
  {"GOCHAR", archChar},
  {"GOEXE", exeSuffix},
- {"GOGCCFLAGS", strings.Join(b.gccCmd(".")[3:], " ")},
  {"GOHOSTARCH", runtime.GOARCH},
  {"GOHOSTOS", runtime.GOOS},
  {"GOOS", goos},
@@ -48,6 +46,12 @@ func mkEnv() []envVar {
  {"GOTOOLDIR", toolDir},
  }
 
+ if goos != "plan9" {
+ cmd := b.gccCmd(".")
+ env = append(env, envVar{"CC", cmd[0]})
+ env = append(env, envVar{"GOGCCFLAGS", strings.Join(cmd[3:], " ")})
+ }
+
  if buildContext.CgoEnabled {
  env = append(env, envVar{"CGO_ENABLED", "1"})
  } else {