Recent gjs changes have made it log most types of messages (including
log() calls) only to a configured log file and not to stderr. So,
set GJS_DEBUG_OUTPUT=stderr to make *stderr* the log file and get
our log() calls back.
Unless we're running gnome-shell from the source directory, we shouldn't
use the .la file as the mutter plugin. Instead, we use the dynamic
library.
Closes: bgo#581327
If Xephyr isn't installed currently src/gnome-shell raises
an exception which isn't at all obvious without looking at
the source. This commit catches the exception and replaces
it with a more informative error message.
