// from a repository.
//
// For more about build flags, see 'go help build'.
//
// For more about modules, see https://golang.org/ref/mod.
//
// For more about using 'go get' to update the minimum Go version and
// suggested Go toolchain, see https://go.dev/doc/toolchain.
//
// For more about specifying packages, see 'go help packages'.
//

// packages. Experimentally, there are diminishing returns with more than
// 4 workers. This was measured on the following machines.
//
// * MacBookPro with a 4-core Intel Core i7 CPU
// * Linux workstation with 6-core Intel Xeon CPU
// * Linux workstation with 24-core Intel Xeon CPU
//
// It is very likely (though not confirmed) that this workload is limited

		fmt.Fprintf(h, "%s=%s\n", key, val)

		if cfg.CleanGOEXPERIMENT != "" {
			fmt.Fprintf(h, "GOEXPERIMENT=%q\n", cfg.CleanGOEXPERIMENT)
		}

		// TODO(rsc): Convince compiler team not to add more magic environment variables,
		// or perhaps restrict the environment variables passed to subprocesses.
		// Because these are clumsy, undocumented special-case hacks