echo
echo
echo "1a) clean build using $FLAGS1"
(export GO_GCFLAGS="$FLAGS1"; sh make.bash)

echo
echo
echo "1b) save go build output for all packages"
for pkg in `go list std`; do
	echo $pkg
	DIR=$GOROOT/src/$pkg
	go build -gcflags "$FLAGS1 -S" -o /dev/null $pkg &> $DIR/old.txt
done

echo
echo
echo "2a) clean build using $FLAGS2"
(export GO_GCFLAGS="$FLAGS2"; sh make.bash)

echo
echo

# GOHOSTARCH=386 on an amd64 machine.
#
# GOARCH: The target architecture for installed packages and tools.
#
# GOOS: The target operating system for installed packages and tools.
#
# GO_GCFLAGS: Additional go tool compile arguments to use when
# building the packages and commands.
#
# GO_LDFLAGS: Additional go tool link arguments to use when
# building the commands.
#

				// missing a C linker.
				t.Logf("HasGoBuild is false on %s", b)
				return
			}
		}

		if strings.Contains(b, "-noopt") {
			// The -noopt builder sets GO_GCFLAGS, which causes tests of 'go build' to
			// be skipped.
			t.Logf("HasGoBuild is false on %s", b)
			return
		}

		t.Fatalf("HasGoBuild unexpectedly false on %s", b)
	}

:: CGO_ENABLED: Controls cgo usage...

				}
				if err != nil {
					return err
				}
				cmd := testenv.Command(t, gotool, "build", "-buildmode=archive", "-o", cgoarchive, "-gcflags=all="+os.Getenv("GO_GCFLAGS"), "mycgo")
				cmd.Dir = filepath.Join(gopath, "src", "mycgo")
				cmd.Env = append(os.Environ(), "GOPATH="+gopath)
				out, err = cmd.CombinedOutput()
				if err != nil {

# GOHOSTARCH=386 on an amd64 machine.
#
# GOARCH: The target architecture for installed packages and tools.
#
# GOOS: The target operating system for installed packages and tools.
#
# GO_GCFLAGS: Additional go tool compile arguments to use when
# building the packages and commands.
#
# GO_LDFLAGS: Additional go tool link arguments to use when
# building the commands.
#