Fixed a nasty bug that dropped symbols that shouldn't have been.

Fixed a nasty bug that dropped symbols that shouldn't have been.

This stemmed from the fact that EQUR symbols somehow made it on to the
symbol declaration list. If such symbol was later .equrundef'd, it would
find it's way back onto the the sdecl list *twice*, with the result
that any symbols that came after it would be summarily discarded into
the ether. Really, really bad mojo.