Support libperl.so under FreeBSD

Support libperl.so under FreeBSD

Subject: Re: 5.003_18 + shared libperl + FreeBSD 3.0-CURRENT

According to Andy Dougherty:
> There's a section in Configure to add such things.  Edit Configure and
> look for a section like

After many tests, here are the two patches that enable use of either shared
or static libperl. Please everyone verify that I didn't broke anything
(especially with the second patch in Makefile.SH)...

Differences between NetBSD & FreeBSD surprise me because we're supposed to
have almost the same ld/ld.so...

p5p-msgid: <Mutt.19970105224149.roberto@keltia.freenix.fr>