Signal runtime errors via a naughty popup

Whenever awesome's C code calls into lua via a protected call, the debug::error
signal is emitted on errors. We now use this to give naughty popups for every
single error that happens. This should help people to notice errors easier.

The only exception are mouse and key grabbers and config loading, those don't go
through debug::error. I guess that means that the grabbers need to be hooked up
to debug::error. :-)

Signed-off-by: Uli Schlachter <psychon@znc.in>

awesomerc.lua.in

@@ -15,6 +15,21 @@ if awesome.startup_errors then
                      title = "Oops, there were errors during startup!",
                      text = awesome.startup_errors })
 end
+
+-- Handle runtime errors after startup
+do
+    local in_error = false
+    awesome.connect_signal("debug::error", function (err)
+        -- Make sure we don't go into an endless error loop
+        if in_error then return end
+        in_error = true
+
+        naughty.notify({ preset = naughty.config.presets.critical,
+                         title = "Oops, an error happened!",
+                         text = err })
+        in_error = false
+    end)
+end
 -- }}}
 
 -- {{{ Variable definitions