symbol 'sin'. cmd/link also processes the cgo_ldflag directives, so that it
knows that the eventual host link command must include the -lm
argument, so that the host linker will be able to find 'sin' in the
math library.

cmd/link Command Line Interface

The go command and any other Go-aware build systems invoke cmd/link
to link a collection of packages into a single binary. By default, cmd/link will

			//   API surface. (If we are running within the "std" module,
			//   vendored dependencies appear as themselves instead of
			//   their "vendor/" standard-library copies.)
			// - 'go list std' does not include commands, which cannot be
			//   imported anyway.
			if ip := pkg.ImportPath; pkg.Standard && ip != "unsafe" && !strings.HasPrefix(ip, "vendor/") && !internalPkg.MatchString(ip) {
				stdPackages = append(stdPackages, ip)
			}

are also treated as invalid.
(Older toolchains ignore `//go:debug` directives entirely.)

The defaults that will be compiled into a main package
are reported by the command:

{{raw `
	go list -f '{{.DefaultGODEBUG}}' my/main/package
`}}

Only differences from the base Go toolchain defaults are reported.

When testing a package, `//go:debug` lines in the `*_test.go`

				Gname:    "strings",
				ModTime:  time.Unix(1314603082, 0),
			}, nil},
			testWrite{"", 0, nil},

			testClose{nil},
		},
	}, {
		// The truncated test file was produced using these commands:
		//   dd if=/dev/zero bs=1048576 count=16384 > /tmp/16gig.txt
		//   tar -b 1 -c -f- /tmp/16gig.txt | dd bs=512 count=8 > writer-big.tar
		file: "testdata/writer-big.tar",
		tests: []testFnc{
			testHeader{Header{

	lineNum       int   // Line number in source file.
	errorLine     int   // Line number of last error.
	errorCount    int   // Number of errors.
	sawCode       bool  // saw code in this file (as opposed to comments and blank lines)
	pc            int64 // virtual PC; count of Progs; doesn't advance for GLOBL or DATA.
	input         []lex.Token
	inputPos      int
	pendingLabels []string // Labels to attach to next instruction.

}

func (w *fileWriter) writeDataDescriptor() error {
	if !w.hasDataDescriptor() {
		return nil
	}
	// Write data descriptor. This is more complicated than one would
	// think, see e.g. comments in zipfile.c:putextended() and
	// https://bugs.openjdk.org/browse/JDK-7073588.
	// The approach here is to write 8 byte sizes if needed without
	// adding a zip64 extra in the local header (too late anyway).
	var buf []byte

		if printed == "" || strings.HasSuffix(printed, ":") { // empty or label
			continue
		}
		seq++

		var hexes string
		switch len(parts) {
		default:
			t.Errorf("%s:%d: unable to understand comments: %s", input, lineno, line)
		case 1:
			// no comment
		case 2:
			// might be printed form or hex
			note := strings.TrimSpace(parts[1])
			if isHexes(note) {
				hexes = note
			} else {
				printed = note