I'm not quite sure what the original intent of this line was, but it
doesn't work in the one call-site the "required" argument is actually
used. The "writable" flag was indexed as a scalar leaving only the
"e" to compare against.
Instead, let's just sort the parsed flags and compare the whole thing.
Also substitute "required" as a pattern, so that pattern based
comparisons may be supported.
47f20650b7