[Libreoffice] clean rebuilds needed

[Norbert Thiebaud]

Considering that

1/ there are still quite a few module to gbuildified. i.e quite some
work to be done involving modification of Makefiles.
2/ tinderboxes don't suffer from that problem because they typically
always do full clean rebuild, and therefore provide a hint as to
whether or not a problem is 'transient-local' vs global

I would not like to have a 'make clean on any touched Makefile' beharior....

Norbert