When compiling on a 64bit Linux distro the dependent
libraries of mysql/postgresql happen to live in the
$prefix/lib64 path instead of $prefix/lib - the configure.in
assumptions of Quickfix get it wrong.
The patch is tested.... but it would be a better option to
allow for two configure.in options with having one for
the header location and the other for the library location.
That's what most of the add-on autoconf macros do.
Tested at https://build.opensuse.org/package/show?package=quickfix&project=home%3Aguidod%3Afixfast
P.S.
Note that both mysql and postgresql have config-binaries that one can ask for the
include/libdir loctions - please check the existing autoconf macros for that at
http://ac-archive.sourceforge.net/ac-archive/ax_lib_postgresql.html
http://ac-archive.sourceforge.net/ac-archive/ax_lib_mysql.html
(not provided in this patch)