decide which.

The obvious thing for cgo to do is to process the preamble, expanding
#includes and processing the corresponding C code. That would require
a full C parser and type checker that was also aware of any extensions
known to the system compiler (for example, all the GNU C extensions) as
well as the system-specific header locations and system-specific

			// atime and ctime fields, which are often left unused.
			//
			// In order to continue reading tar files created by former, buggy
			// versions of Go, we skeptically parse the atime and ctime fields.
			// If we are unable to parse them and the prefix field looks like
			// an ASCII string, then we fallback on the pre-Go1.8 behavior
			// of treating these fields as the USTAR prefix field.
			//

The new [ParseCookie] function parses a Cookie header value and
returns all the cookies which were set in it. Since the same cookie
name can appear multiple times the returned Values can contain
more than one value for a given key.

The new [ParseSetCookie] function parses a Set-Cookie header value and

func (w *Walker) parseFile(dir, file string) (*ast.File, error) {
	filename := filepath.Join(dir, file)
	if f := parsedFileCache[filename]; f != nil {
		return f, nil
	}

	f, err := parser.ParseFile(fset, filename, nil, parser.ParseComments)
	if err != nil {
		return nil, err
	}
	parsedFileCache[filename] = f

	return f, nil
}

// Disable before debugging non-obvious errors from the type-checker.