Debugging MesaLib

[tlaronde%kergis.com@localhost]

There is a problem with MesaLib, gallium namely
gallium/auxiliary/vl/vl_mpeg12_decoder.c

A function is trying to define values in a structure expecting 3
planes; there is only one and the function is called with NULL
pointers that trigger assertions.

Furthermore, what is returned, even if the fault is caught avoiding
to abort at this stage, can be a NULL pointer (if there was a problem),
but this is not tested in the callers except by another assert that
aborts as well (in brief: the code expects that everything should work
or it crashes). And it crashes happily in various circumstances.

I'm trying to make it at least not crash by modifying the C
sources. But the build framework uses meson/ninja, and it doesn't
detect a change in the source file so do not regenerate the object file.

The question:

How to make meson/ninja or the pkgsrc framework rewalk the tree in
order to update the corresponding objects when some sources have changed 
avoiding to have to restart from the beginning (extract, patch,
configure, build) and rebuilding the ~2000 other untouched objects?

BTW: simply removing the sentry .build_done doesn't work, because it
is not make that is used.

TIA for any tip,
-- 
        Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
                     http://www.kergis.com/
                    http://kertex.kergis.com/
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