// descriptors and should account for either case when reading
	// ZIP files to ensure compatibility."
	//
	// dataDescriptorLen includes the size of the signature but
	// first read just those 4 bytes to see if it exists.
	if _, err := io.ReadFull(r, buf[:4]); err != nil {
		return err
	}
	off := 0
	maybeSig := readBuf(buf[:4])
	if maybeSig.uint32() != dataDescriptorSignature {
		// No data descriptor signature. Keep these four

			paxHdrs[paxSchilyXattr+k] = v
		}
		whyOnlyPAX = "only PAX supports Xattrs"
		format.mayOnlyBe(FormatPAX)
	}
	if len(h.PAXRecords) > 0 {
		for k, v := range h.PAXRecords {
			switch _, exists := paxHdrs[k]; {
			case exists:
				continue // Do not overwrite existing records
			case h.Typeflag == TypeXGlobalHeader:
				paxHdrs[k] = v // Copy all records
			case !basicKeys[k] && !strings.HasPrefix(k, paxGNUSparse):

may include command line options.

The cgo tool will always invoke the C compiler with the source file's
directory in the include path; i.e. -I${SRCDIR} is always implied. This
means that if a header file foo/bar.h exists both in the source
directory and also in the system include directory (or some other place
specified by a -I flag), then "#include <foo/bar.h>" will always find the
local version in preference to any other version.

			for _, c := range blk {
				if c == '\n' {
					cntNewline++
				}
			}
		}
		return nil
	}

	// nextToken gets the next token delimited by a newline. This assumes that
	// at least one newline exists in the buffer.
	nextToken := func() string {
		cntNewline--
		tok, _ := buf.ReadString('\n')
		return strings.TrimRight(tok, "\n")
	}

	// Parse for the number of entries.

	if !strings.Contains(f, "(") {
		return f
	}
	return spaceParensRx.ReplaceAllString(f, "")
}

// portRemoved reports whether the given port-specific API feature is
// okay to no longer exist because its port was removed.
func portRemoved(feature string) bool {
	return strings.Contains(feature, "(darwin-386)") ||
		strings.Contains(feature, "(darwin-386-cgo)")
}