Get the gphoto2-2.1.0 tarball

Untar it

Go into the gphoto2-2.1.0 directory
type:
	cat /path/to/cl20.patch | patch -p2

It should say:
patching file camlibs/agfa-cl20/agfa_cl20.c
patching file camlibs/agfa-cl20/CVS/CVS/Entries
patching file camlibs/agfa-cl20/CVS/CVS/Repository
patching file camlibs/agfa-cl20/CVS/CVS/Root
patching file camlibs/agfa-cl20/CVS/Entries
patching file camlibs/agfa-cl20/CVS/Repository
patching file camlibs/agfa-cl20/CVS/Root
patching file camlibs/agfa-cl20/Makefile.am
patching file camlibs/agfa-cl20/Makefile.in
patching file camlibs/agfa-cl20/README
patching file camlibs/agfa-cl20/STATUS
patching file configure

Then you're good to go :-)

./configure --with-drivers=agfa-cl20 --without-ltdl --prefix=/usr --without-exif

(--without-ltdl and --without-exif are important!!)