This page details how to modify the mingw-configure script in the situation where the cross compilation environment needs to take into account libraries (through pkg-config and their .pc files) installed into two different locations, such as:
the dev ZIP files containing compiled versions of GLib, GTK+ and related dependencies have been uncompressed in one directory pointed by the value of the GTK_PREFIX environment variable
the installation prefix of libgda is different (for example /local/EXTRA/Win32), to be set in the MY_PREFIX environment variable.
The modified mingw-configure script which takes into account the GTK_PREFIX and the MY_PREFIX environment variables, is available as: mingw-configure.
Before using that modified version, it is necessary to modify the prefix=... line of all the .pc files in the $GTK_PREFIX/lib/pkgconfig directory with to set it to prefix=<value of $GTK_PREFIX> (this modification is made mandatory because the original script forced pkg-config to override the prefix value with $GTK_PREFIX which is not possible anymore since there are now two possible prefixes).