diff --git a/configure.ac b/configure.ac
index 616fa55b8aa..bea28338090 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5677,12 +5677,14 @@ Configured for '${canonical}'.
   Where do we find X Windows header files?                ${x_includes:-$emacs_standard_dirs}
   Where do we find X Windows libraries?                   ${x_libraries:-$emacs_standard_dirs}"])
 
+#### Please respect alphabetical ordering when making additions.
 optsep=
 emacs_config_features=
-for opt in XAW3D XPM JPEG TIFF GIF PNG RSVG CAIRO IMAGEMAGICK SOUND GPM DBUS \
-  GCONF GSETTINGS GLIB NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT \
-  LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS X_TOOLKIT OLDXMENU X11 XDBE XIM \
-  NS MODULES THREADS XWIDGETS LIBSYSTEMD JSON PDUMPER UNEXEC LCMS2 GMP; do
+for opt in ACL CAIRO DBUS FREETYPE GCONF GIF GLIB GMP GNUTLS GPM GSETTINGS \
+ HARFBUZZ IMAGEMAGICK JPEG JSON LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 \
+ M17N_FLT MODULES NOTIFY NS OLDXMENU PDUMPER PNG RSVG SOUND THREADS TIFF \
+ TOOLKIT_SCROLL_BARS UNEXEC X11 XAW3D XDBE XFT XIM XPM XWIDGETS X_TOOLKIT \
+ ZLIB; do
 
     case $opt in
       PDUMPER) val=${with_pdumper} ;;