meson.eclass: MESON_AUTO_DEPEND support
Make it possible to use the meson eclass without it automatically adding
meson to DEPEND. Intended for cases where meson usage is conditional
(e.g. hidden behind a USE flag).
This is a direct copy of the AUTOTOOLS_AUTO_DEPEND functionality &
implementation from autotools.eclass, including the guard for multiple
inheritance.
Closes: https://bugs.gentoo.org/626054
Signed-off-by: Robin H. Johnson <robbat2@gentoo.org>
Signed-off-by: Mike Gilbert <floppym@gentoo.org>