xcbproto: Meson added + doc

[tlaronde at kergis.com]

I have added Meson files (plus python related POSIX.2 shell utilities)
to xcbproto (no merge request yet):

https://gitlab.freedesktop.org/tlaronde/xcbproto

I have written also notes explaining the process chunk by chunk here:

https://notes.kergis.com/x11_building.html

(I will augment the .gitlab-ci.yml for Meson built and comparison with
Autotools generated data, and add a section in the online notes
above.)

One more thing I'd like to have feedback about:

An utility: auto-meson-pc-cmp.sh has been added to xorg/util/modular
for the C.I. allowing to compare semantically the pkgconfig file
generated (and not lettre by letter in order to not he hampered by GNU
names).

For the python related utilities: find_vpython.sh (find a python
interpreter matching a version condition) and compile_py.sh (self
explanatory), they have to be distributed.

But instead of recopying them other and other in modules needing them
(for Meson), is there an xorg module that is required for any building
(like imake was a request before) where such utilities could be
placed, perhaps with an "xorg_" or "x11_" prefix so that they could
be used by Meson instructions files?
-- 
        Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
                     http://www.kergis.com/
                    http://kertex.kergis.com/
                     http://nunc-et-hic.fr/
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