# locate libtiff. | grep -i "/lib/"
/usr/local/lib/libtiff.a
/usr/local/lib/libtiff.la
/usr/local/lib/libtiff.so
/usr/local/lib/libtiff.so.4

[root@testBSD01]:/usr/local/src/spandsp-0.0.3-->
./configure --libdir=/usr/local/lib/
[snip]
checking for TIFFOpen in -ltiff... no
configure: error: "Can't build without libtiff (does your system require a libtiff-devel package?)"
[/snip]