Modified bcron to display an error when cron is installed.

base/bcron/bcron.conf

@@ -13,6 +13,11 @@
 # GNU General Public License can be found in the file COPYING.
 # --- SDE-COPYRIGHT-NOTE-END ---
 
+# This package is mutually exclusive with cron.
+if pkginstalled cron; then
+	echo_error "CLASH: cron and $pkg don't go together."
+fi
+
 pkgprefix -t bglibs
 
 sysconfdir=$sysconfdir/$pkg