[GRASS5] Libgrass_gis on Mingw - open.c patch

[Javier A. Yebrin]

> how about a list of what doesn't build?
> 
Something like:

r.digit
r.out.png
r.out.ppm3
r.out.tiff
r.random
r.region
r.resamp.rst
r.surf.fractal
r.surf.gauss
r.surf.idw2
r.surf.random
r.terraflow
r.timestamp
r.to.vect

Some of them will not work because they need a GUI (r.digit). Others maybe
because of wrong configure flags (r.out.***).
Cheers,

Javier