i'm trying to install gthumb -2.4.1 to a newly installed mdk10.0. the installation stops at libgnomeprint-2.2 with an error:

Package libgnomeprint-2.2 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libgnomeprint-2.2.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libgnomeprint-2.2' found

$ locate libgnomeprint-2.2
/usr/share/locale/fi/LC_MESSAGES/libgnomeprint-2.2.mo

$ locate libgnomeprint
/usr/share/doc/libgnomeprint-2.4.2
/usr/share/doc/libgnomeprint-2.4.2/ChangeLog
... (many lines clipped) ...
/usr/share/libgnomeprint/2.4.2
/usr/share/libgnomeprint/2.4.2/models
...
/usr/lib/libgnomeprint/2.4.2
/usr/lib/libgnomeprint/2.4.2/modules
...

$ locate pkgconfig
/usr/share/doc/pkgconfig-0.15.0
...
/usr/lib/pkgconfig
/usr/lib/pkgconfig/gnome-mime-data-2.0.pc
...
(libgnomeprint*.* is missing from this path)

$ echo $PKG_CONFIG_PATH
/usr/lib/pkgconfig:

what is the libgnomeprint-2.2 (or 2.4.2) .pc file? where can i get it?

I did this once - and I'm not sure exactly how I did it - but basically, it's like this:

pkg-config needs to realize that this lib is installed. Do a man pkg-config, and see what it says.
You should find that .pc file somewhere in that dir (/usr/share/doc/libgnomeprint-2.4.2)
Once you have it, you have to run a command to add it to pkg-config. It's not as simple as editing a file if I remember right.
Anyway, you run the command, point it to the .pc file, and it will update the config file for you.
Do a ./configure again, and you should be good to go.

You must pass the correct path of the libraries to ./configure.
Try ./configure --help for knowledge how to pass the correct path, usually "-with-path_libraries" it works.

Try typing (as root): ldconfig