"cmd/go/internal/cfg"
	"cmd/go/internal/fsys"
	"cmd/go/internal/gover"
	"cmd/go/internal/load"
	"cmd/go/internal/str"
	"cmd/internal/quoted"
	"crypto/sha1"
)

// Tests can override this by setting $TESTGO_TOOLCHAIN_VERSION.
var ToolchainVersion = runtime.Version()

// The Go toolchain.

type gcToolchain struct{}

func (gcToolchain) compiler() string {
	return base.Tool("compile")
}

	if os.Getenv("CMDGO_TEST_RUN_MAIN") != "" {
		cfg.SetGOROOT(cfg.GOROOT, true)
		gover.TestVersion = os.Getenv("TESTGO_VERSION")
		toolchain.TestVersionSwitch = os.Getenv("TESTGO_VERSION_SWITCH")
		if v := os.Getenv("TESTGO_TOOLCHAIN_VERSION"); v != "" {
			work.ToolchainVersion = v
		}

		if testGOROOT := os.Getenv("TESTGO_GOROOT"); testGOROOT != "" {
			// Disallow installs to the GOROOT from which testgo was built.