When searching for unixODBC, we want to use
the libdir passed in to autotools (--libdir)
to ensure that we find the library
for the correct ABI.
It is possible that we pick up the wrong
copy from e.g. /usr/lib/ where a 32-bit
unixODBC copy of the library exists
when we're in the middle of a 64-bit build.
Use ${libdir} to ensure we respect
any preferences/information given and
search for ODBC in the right place.
Note that this previously affected
us with iODBC but that's since been
resolved by using their
iodbc-config binary.
Bug: https://bugs.gentoo.org/697568
Signed-off-by: Sam James <sam@gentoo.org>
