This is necessary since isGnuLibC() is true for hurd, so we need to be able to
represent a glibc version for it.
Also add an Os.TaggedVersionRange.gnuLibCVersion() convenience function.
The strlcpy symbol was added in v2.38, so this is a handy symbol for
creating binaries that won't run on relatively modern systems (e.g., mine,
that has glibc 2.36 installed).
