build: fix regressions with the -dlgo change (#21831)

This fixes cross-build and mobile framework failures.
It also disables the mac test builder because it was failing
all the time in hard to understand ways and we can't afford
it anymore under Travis CI's new pricing.

.travis.yml

@@ -55,24 +55,6 @@ jobs:
       script:
         - go run build/ci.go test -coverage $TEST_PACKAGES
 
-    - stage: build
-      os: osx
-      osx_image: xcode11.3
-      go: 1.15.x
-      env:
-        - GO111MODULE=on
-      script:
-        - echo "Increase the maximum number of open file descriptors on macOS"
-        - NOFILE=20480
-        - sudo sysctl -w kern.maxfiles=$NOFILE
-        - sudo sysctl -w kern.maxfilesperproc=$NOFILE
-        - sudo launchctl limit maxfiles $NOFILE $NOFILE
-        - sudo launchctl limit maxfiles
-        - ulimit -S -n $NOFILE
-        - ulimit -n
-        - unset -f cd # workaround for https://github.com/travis-ci/travis-ci/issues/8703
-        - go run build/ci.go test -coverage $TEST_PACKAGES
-
     # This builder does the Ubuntu PPA upload
     - stage: build
       if: type = push

build/ci.go

@@ -243,7 +243,7 @@ func doInstall(cmdline []string) {
 	}
 
 	// Configure C compiler.
-	if *cc == "" {
+	if *cc != "" {
 		gobuild.Env = append(gobuild.Env, "CC="+*cc)
 	} else if os.Getenv("CC") != "" {
 		gobuild.Env = append(gobuild.Env, "CC="+os.Getenv("CC"))
@@ -259,6 +259,9 @@ func doInstall(cmdline []string) {
 	// Put the default settings in.
 	gobuild.Args = append(gobuild.Args, buildFlags(env)...)
 
+	// We use -trimpath to avoid leaking local paths into the built executables.
+	gobuild.Args = append(gobuild.Args, "-trimpath")
+
 	// Show packages during build.
 	gobuild.Args = append(gobuild.Args, "-v")
 
@@ -294,8 +297,6 @@ func buildFlags(env build.Environment) (flags []string) {
 	if len(ld) > 0 {
 		flags = append(flags, "-ldflags", strings.Join(ld, " "))
 	}
-	// We use -trimpath to avoid leaking local paths into the built executables.
-	flags = append(flags, "-trimpath")
 	return flags
 }
 
@@ -318,6 +319,7 @@ func localGoTool(goroot string, subcmd string, args ...string) *exec.Cmd {
 
 // goToolSetEnv forwards the build environment to the go tool.
 func goToolSetEnv(cmd *exec.Cmd) {
+	cmd.Env = append(cmd.Env, "GOBIN="+GOBIN)
 	for _, e := range os.Environ() {
 		if strings.HasPrefix(e, "GOBIN=") || strings.HasPrefix(e, "CC=") {
 			continue
@@ -514,7 +516,7 @@ func doDebianSource(cmdline []string) {
 	gobundle := downloadGoSources(*cachedir)
 
 	// Download all the dependencies needed to build the sources and run the ci script
-	srcdepfetch := goTool("install", "-n", "./...")
+	srcdepfetch := goTool("mod", "download")
 	srcdepfetch.Env = append(os.Environ(), "GOPATH="+filepath.Join(*workdir, "modgopath"))
 	build.MustRun(srcdepfetch)