Generate config.h

This allows us to remove a lot of #ifdef's. Either we want to use
a config.h or we don't. Since we'll want it for e.g. optional gsound
support later on let's have it.

src/server-context-service.c

@@ -15,9 +15,7 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-#ifdef HAVE_CONFIG_H
 #include "config.h"
-#endif  /* HAVE_CONFIG_H */
 
 #include <gtk/gtk.h>
 #include <glib/gi18n.h>