Avoid depending on gdb for replacing an existing panel, since it
requires debuginfo and gdb installed.
Instead we grab the org.gnome.Panel DBus name, using DBus name
replacement semantics.
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.
