Help with libinput debug

[Corentin Marciau]

Hello,

I'm trying to build and test libinput but I can't figure out how.
I followed the documentation :

	meson --prefix=/usr builddir
	ninja -C builddir
	sudo ninja -C builddir install
	sudo udevadm hwdb --update

All went so well that I cried of joy. Then I tried to add something like 
a log message in evdev-mt-touchpad-tap.c @ tp_tap_touch_handle_event to 
see if my modifs where taken into account :

	case TAP_EVENT_RELEASE:
		evdev_log_debug(tp->device,
		                "Isn't that a nice tap ?\n");

But nothing came out in ~/.local/share/xorg/Xorg.0.log, where I expected 
the logs would go. Even though I :
- Restarted X
- Checked the correct lib was linked to libinput.so
- Recompiled with libinput->log_priority = LIBINPUT_LOG_PRIORITY_DEBUG;
- Checked with lsof that libinput was using
   ~/.local/share/xorg/Xorg.0.log
- Checked in the sources of libinput_drv.so that the log priority was
   set to Debug

Does anyone has a clue about what I did wrong ? And generally speaking, 
how do you test your modifications to libinput ?

Thanks for any help :)
Corentin