all: use cmd.Environ rather than os.Environ

Added in Go 1.19, this keeps os/exec's default environment logic,
such as ensuring that $PWD is always set.

bench_test.go

@@ -79,12 +79,12 @@ func BenchmarkBuild(b *testing.B) {
 		garbleCache := filepath.Join(tdir, "garble-cache")
 		qt.Assert(b, qt.IsNil(os.RemoveAll(garbleCache)))
 		qt.Assert(b, qt.IsNil(os.Mkdir(garbleCache, 0o777)))
-		env := append(os.Environ(),
+		env := []string{
 			"RUN_GARBLE_MAIN=true",
-			"GOCACHE="+goCache,
+			"GOCACHE=" + goCache,
-			"GARBLE_CACHE="+garbleCache,
+			"GARBLE_CACHE=" + garbleCache,
 			"GARBLE_WRITE_ALLOCS=true",
-		)
+		}
 		args := []string{"build", "-v", "-o=" + outputBin, sourceDir}
 
 		for _, cached := range []bool{false, true} {
@@ -95,7 +95,7 @@ func BenchmarkBuild(b *testing.B) {
 			}
 
 			cmd := exec.Command(os.Args[0], args...)
-			cmd.Env = env
+			cmd.Env = append(cmd.Environ(), env...)
 			cmd.Dir = sourceDir
 
 			cachedStart := time.Now()

internal/linker/linker.go

@@ -196,7 +196,7 @@ func buildLinker(workingDir string, overlay map[string]string, outputLinkPath st
 	//   go version -m ~/tip/pkg/tool/linux_amd64/link
 	//
 	// and which can be done from Go via debug/buildinfo.ReadFile.
-	cmd.Env = append(os.Environ(),
+	cmd.Env = append(cmd.Environ(),
 		"GOENV=off", "GOOS=", "GOARCH=", "GOEXPERIMENT=", "GOFLAGS=",
 	)
 	// Building cmd/link is possible from anywhere, but to avoid any possible side effects build in a temp directory

scripts/bench_literals.go

@@ -142,7 +142,7 @@ func main() {
 	garbleBin := buildTestGarble(tdir)
 	args := append([]string{"-seed", garbleSeed, "-literals", "test", "-bench"}, os.Args[1:]...)
 	cmd := exec.Command(garbleBin, args...)
-	cmd.Env = append(os.Environ(),
+	cmd.Env = append(cmd.Environ(),
 		// Explicitly specify package for obfuscation to avoid affecting testing package.
 		"GOGARBLE="+moduleName,
 		"GARBLE_TEST_LITERALS_OBFUSCATOR_MAP="+strings.Join(packageToObfuscatorIndex, ","),