Fix startup of GNOME under GDM
Includes two important commits:
- community/gnome-shell: do not set cap_sys_nice: The way the current gnome installation works, setting cap_sys_nice
for gnome-shell makes it crash at startup. The reason is that
gnome-shell creates a dbus session on startup, which is only successful
if the process does not need to be treated securely (through
getauxval(AT_SECURE)
). In consequence, setting some capability in the binary, which is run under unprivileged gdm user, makes it impossible to start the session. - community/gnome-session: depends on mesa for opengl acceleration: gnome-session requires either hardware of software acceleration for opengl or opengles, otherwise it will reject to start