[gnome-db] configure error: gobject-introspection-1.0 is not installed

Hi All,
I would like to play a little bit with libgda, libgda-ui and (the new 
gobject-enabled) C++ and/or Vala bindings, so I just cloned libgda from 
the GIT repository and I tried to configure it with the 
gobject-introspection support (and a few other things):

$ ./configure --enable-vala --enable-introspection --enable-gda-gi 
--enable-gdaui-gi --with-ui 
--with-postgres-libdir-name=/usr/include/postgres

and I've got this error:

checking for gobject-introspection... configure: error: 
gobject-introspection-1.0 is not installed

but, the gobject-introspection package is installed:

$ dpkg -l | grep gobject-introspection*
ii  gobject-introspection                  1.30.0-0ubuntu2 
            Generate interface introspection data for GObject libraries
ii  python-gobject                         3.0.0-0ubuntu4 
            Python 2.x bindings for gobject-introspection libraries

and the the config.ac seems to be performing the required check:

GOBJECT_INTROSPECTION_CHECK([0.6.5]) ... etc...

So the info contained in:

http://developer.gnome.org/anjuta-build-tutorial/stable/library-autotools.html.en 


... is not of help.

How can I fix this problem? Did I misunderstand anything?

Thanks

PS: I'm using a Linux Mint 12 (based on a Ubuntu 11.10 Oneiric Ocelot).

PS2: libgda (and libgda-ui, demos, tools, etc.) compiles fine without 
these gobject/vala configure switches, both from the CL and from Anjuta.