Another FreeBSD 3.1 underscore fix

[Rich Wales]

In addition to the "underscore" problem I reported earlier today with
FreeBSD 3.1, I ran into problems with loading dynamic modules.

The "configure" file defines the symbol DLSYM_NEEDS_UNDERSCORE, which
is used by cipher/dynload.c to determine the symbol names it looks for
in an extension module.

DLSYM_NEEDS_UNDERSCORE should =NOT= be defined for FreeBSD 3.x, since
(as I mentioned earlier) the external symbols in this system don't
start with underscore characters.

Since I'm not very familiar with "autoconf", I'm not sure what the real
way is to do this.  I did a quick-and-dirty patch of the "configure"
file, but I assume Werner will know how to do it correctly.

Rich Wales         richw at webcom.com         http://www.webcom.com/richw/
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