Issue detected while building libgda against mbdtools 0.9.3:

[   66s] /usr/include/mdbtools.h:38:10: fatal error: mdbfakeglib.h: No such
file or directory
[   66s]    38 | #include <mdbfakeglib.h>

The problem there is that /usr/include/mdbtools.h does

#ifdef HAVE_GLIB
#include <glib.h>
#else
#include <mdbfakeglib.h>
#endif


This is probably something it tries to do for its own build system, but when
building libgda, this now somewhat relies on 'something' setting HAVE_GLIB.

One easy way out would be to inject -DHAVE_GLIB into the .pc file (after all,
it has requires: glib-2.0, so we are sure to have glib)

I tested that on a local build, which does indeed work around the issue in
libgda
(but then have different build failures, likely coming from API changes though)