How to point an emacs build to gif libs

[Harry Putnam]

setup Solaris OS (openindiana-hipster)

Trying to figure out how to tell configure where to look for gif
libraries by using ./configure --help shows --libdir= so I tried using
that to point /opt/csw/lib:/opt/csw/lib/amd64/

Where things like: libungif.so libgif.so.4.1.7 libgif.so and several
more like those but ./configure ends with:

My ./configure line:

 PATH=$PATH ./configure --prefix=/usr/local/src/vcs/git/test
   --with-x=yes --with-gif=yes --libdir=/opt/csw/lib:/opt/csw/lib/amd64
     --with-imagemagick=yes --with-x-toolkit=athena

(the PATH= stuff was there to cure a problem where ./configure was
finding the wrong (old) verion of makeinfo... the PATH variable seemed
to head it the right way /opt/csw/bin/)

So with that ./configure line, it ends with:

,----
| [...]
| configure: error: The following required libraries were not found:
|      libgif/libungif
| Maybe some development libraries/packages are missing?
| If you don't want to link with them give
|      --with-gif=no
| as options to configure
`----

Having emacs built with gif or not is really small potatoes, my query
is more to for once and for all... learn how to tell ./configure some
kinds of things.