WARNING: On a 64-bit multiarch OS, this will by default install libclamav
into /usr/local/lib64, if your system uses /usr/local/lib for 32bit apps.
If the system uses /usr/local/lib for 64-bit apps and lib32 for 32bit apps,
there is no change (unless you use -m32).
git-svn: trunk@4284
by default current prefix is also searched
allow to specify libb2 location, by using --with-bz2-prefix,
by default current prefix is also searched
locating gmp and bz2 works by default on OpenBSD (bb #301)
move local m4 macros to m4/
import lib-link.m4 and dependent files
quoting for autoconf macros (bb #452)
git-svn: trunk@3566
