Pam authentication

[kotontrion]

Adds methods to Utils to be able to authenticate against Pam.

Utils.authenticate("password")
  .then(res => {
    //auth was successful
  })
  .catch(logError)
Utils.authenticate_user("username", "password")
  .then(res => {
    //auth was successful
  })
  .catch(logError)

Note:
This is the first time I wrote a gir lib and it's been a long time since I used C, so it might be a good idea to check this a bit more in detail.

[kotontrion]

I just thought, this should probably made async. Depending on the pam configuration, there may be a delay when authentication fails. This will currently freeze ags for that time (I didn't test this though).

[Aylur]

It definitely needs to be async yes

[kotontrion]

I noticed an issue with this, which is quite easy fixable, I'm just writing this here to remember it.

This will create a libpam.so library in the libdir. The default libdir currently is /usr/lib, so this will overwrite the libpam.so file of the Pam package, and therefore breaking pam.
This is fixable by either renaming our Pam module to something like libagspam.so or something similar, or even better use /usr/lib/ags as the default libdir. This is already done by the AUR package, and the reason I didn't notice this issue until now.

[Aylur]

I think its fine, Gvc is also installed there, and we didn't get any feedback about it being an issue
But if we decide to rename it, I would like to avoid having ags in its name, because the eventual rebranding for the gtk4 version. libpamauth or maybe something like libgutils because I would also like to support input inhibiting sometime which needs to be in c too

[kotontrion]

Well actually, there was a complaint on discord a few month ago, because gvc installs to /usr/lib/libgvc.so which conflicts with the graphviz package. That's the reason why the aur package has the --libdir parameter set to /usr/lib/ags.

This is only an issue if installed from source following the instructions on the wiki, as there the libdir is set to /usr/lib. So if someone does not know about this and follows the wiki for manual installation ends up with a broken pam install (as Pam is installed on almost every system). This should be avoided. Maybe at least add the --libdir parameter to meson in the wiki then.

I would also like to support input inhibiting

If you are talking about the input inhibitor Wayland protocol, that's been deprecated for a while now. For lockscreens the ext-session-lock protocol should be used.