--- a/build/unix/mozconfig.gtk
+++ b/build/unix/mozconfig.gtk
@@ -1,12 +1,8 @@
-# To do try builds with Gtk+2, uncomment the following line, and remove
-# everything after that.
-#ac_add_options --enable-default-toolkit=cairo-gtk2
-
 TOOLTOOL_DIR=${TOOLTOOL_DIR:-$topsrcdir}
 
 # $TOOLTOOL_DIR/gtk3 comes from tooltool, and must be included in the tooltool manifest.
 if [ -z "$PKG_CONFIG_LIBDIR" ]; then
   echo PKG_CONFIG_LIBDIR must be set >&2
   exit 1
 fi
 export PKG_CONFIG_SYSROOT_DIR="$TOOLTOOL_DIR/gtk3"