[GRASS5] Platform for next generation UI

[Māris Nartišs]

For non-programmer it seems to be trivial -
G_open_raster_new() - deadlock;
G_open_raster_old() - softlock.

Only big problem - what if module forgets to call G_close_cell() (i.e.
segfaults).

Anyway - if we create new UI, adding calls for map locking shouldn't
be big problem, if locking is done per mapset base - independent from
user/session.

Just to keep flame,
Maris.

> Each module would need to acquire locks on all of the maps which it
> will be using at the outset, and release them all upon completion.
>
> This really needs to be done in the module itself, as the libraries
> only get to "see" individual maps being opened and closed.
>
> --
> Glynn Clements <glynn at gclements.plus.com>