Requirements may be added, updated, and removed with 'go get'.
The vendor directory may be updated with 'go mod vendor'.
A typical sequence might be:

    cd src  # or src/cmd
    go get golang.org/x/net@master
    go mod tidy
    go mod vendor

Use caution when passing '-u' to 'go get'. The '-u' flag updates
modules providing all transitively imported packages, not only

../mkzip ../../zoneinfo.zip
cd ../..

files="update.bash zoneinfo.zip"
modified=true
if git diff --quiet $files; then
	modified=false
fi

if [ "$1" = "-work" ]; then
	echo Left workspace behind in work/.
	shift
else
	rm -rf work
fi

if ! $modified; then
	echo No updates needed.
	exit 0
fi

echo Updated for $CODE/$DATA: $files

commitmsg="lib/time: update to $CODE/$DATA

      placeholder: |
        Go: devel go1.22-0262ea1ff9 Thu Oct 26 18:46:50 2023 +0000
        Scanner: govulncheck@v1.0.2-0.20231108200754-fcf7dff7b242
        DB: https://vuln.go.dev
        DB updated: 2023-11-21 15:39:17 +0000 UTC
    validations:
      required: true
  - type: textarea
    id: reproduce-latest-version
    attributes:
      label: "Does this issue reproduce at the latest version of golang.org/x/vuln?"

To override these defaults, a main package's source files
can include one or more `//go:debug` directives at the top of the file
(preceding the `package` statement).
Continuing the `panicnil` example, if the module or workspace is updated
to say `go` `1.21`, the program can opt back into the old `panic(nil)`
behavior by including this directive:

	//go:debug panicnil=1

Starting in Go 1.21, the Go toolchain treats a `//go:debug` directive

// it has sufficient capacity, the destination is resliced to accommodate the
// new elements. If it does not, a new underlying array will be allocated.
// Append returns the updated slice. It is therefore necessary to store the
// result of append, often in the variable holding the slice itself:
//
//	slice = append(slice, elem1, elem2)
//	slice = append(slice, anotherSlice...)
//

<code>Sizeof</code> are compile-time constant expressions of type <code>uintptr</code>.
</p>

<p>
The function <code>Add</code> adds <code>len</code> to <code>ptr</code>
and returns the updated pointer <code>unsafe.Pointer(uintptr(ptr) + uintptr(len))</code>.
The <code>len</code> argument must be of integer type or an untyped <a href="#Constants">constant</a>.

	flag.Parse()
	for _, c := range contexts {
		c.Compiler = build.Default.Compiler
	}
	build.Default.GOROOT = testenv.GOROOT(nil)

	os.Exit(m.Run())
}

var (
	updateGolden = flag.Bool("updategolden", false, "update golden files")
)

func TestGolden(t *testing.T) {
	if *flagCheck {
		// slow, not worth repeating in -check
		t.Skip("skipping with -check set")
	}

	testenv.MustHaveGoBuild(t)

					// function. A goroutine can switch to a new stack if the current stack is too small (see morestack function).
					// This changes the SP, thus we have to update the SP used by the imported function.

					// func wasmExit(code int32)
					"runtime.wasmExit": (sp) => {
						sp >>>= 0;
						const code = this.mem.getInt32(sp + 8, true);
						this.exited = true;

It will replace nil with 0 in the appropriate places.

The EGLDisplay case was introduced in Go 1.12. Use the egl rewrite
to auto-update code from Go 1.11 and earlier:

	go tool fix -r egl <pkg>

The EGLConfig case was introduced in Go 1.15. Use the eglconf rewrite
to auto-update code from Go 1.14 and earlier:

	go tool fix -r eglconf <pkg>

# Using cgo directly

Usage:

	case magic == magicGNU && version == versionGNU:
		return FormatGNU
	default:
		return formatV7
	}
}

// setFormat writes the magic values necessary for specified format
// and then updates the checksum accordingly.
func (b *block) setFormat(format Format) {
	// Set the magic values.
	switch {
	case format.has(formatV7):
		// Do nothing.
	case format.has(FormatGNU):