Log Message:
news/pan: update to 0.150.

Switch back to fetching the distfile from gitlab.gnome.org, since
a) the configure.ac file no longer uses the problematic "$Format:%d$"
   which can change if commits are added (only the stable
   GIT_HASH='$Format:%h$' is left). Hopefully this fixes the problem.
b) the upstream of the pre-made tarball is getting behind
Also there are some pkglint fixes.

The main points of this release are:
- Dropped support for GMime2. Only Gmime3 is supported
- Gtk3 is now default build, Gtk2 is deprecated

15fcc65 set maximum number of serveur connections to 20 (Dominique Dumont)
431f56f Nuke $GIT_REMOTE if not obtained by git config (Petr Kovar)