Using https://gitlab.freedesktop.org/mobile-broadband/ModemManager.git to download the source code.
Added compile option to compile qrtr support.
Enabled lto and additional gcc flags for perfomance and less size.
Modified to use meson as upstream has abandoned autotools.
Removed BUILD_PARALLEL options. These are default with ninja/meson.

Signed-off-by: Maxim Anisimov <maxim.anisimov.ua@gmail.com>
(cherry picked from commit 6ae8b15d68)