function <code>Syscall</code> in package <code>syscall</code> should
use the name <code>·Syscall</code> instead of the equivalent name
<code>syscall·Syscall</code> in its <code>TEXT</code> directive).
For more complex situations, explicit annotation is needed.
These annotations use pseudo-instructions defined in the standard
<code>#include</code> file <code>funcdata.h</code>.
</p>

<p>
If a function has no arguments and no results,

		is1x0 = true
	case major != "" || minor != "":
		return nil, nil // Unknown GNU sparse PAX version
	case hdr.PAXRecords[paxGNUSparseMap] != "":
		is1x0 = false // 0.0 and 0.1 did not have explicit version records, so guess
	default:
		return nil, nil // Not a PAX format GNU sparse file.
	}
	hdr.Format.mayOnlyBe(FormatPAX)

	// Update hdr from GNU sparse PAX headers.

	}
	if context.CgoEnabled {
		ctags["cgo"] = true
	}
	for _, tag := range context.BuildTags {
		ctags[tag] = true
	}
	// TODO: ReleaseTags (need to load default)
	key := dir

	// explicit on GOOS and GOARCH as global cache will use "all" cached packages for
	// an indirect imported package. See https://github.com/golang/go/issues/21181
	// for more detail.
	tags = append(tags, context.GOOS, context.GOARCH)