Enchant-2.1.1 was recently released and it removed some deprecated APIs which WebKitGtk is still using. Trying to build WebKitGtk-2.18.0 against Enchant-2.1.1 results in following error:
/home/armin/src/pacman/pkgbuild/webkitgtk/src/webkitgtk-2.18.0/Source/WebCore/platform/text/enchant/TextCheckerEnchant.cpp:132:9: error: use of undeclared identifier 'enchant_dict_free_suggestions'
Refer to commit  for details.
Easy bug fix (taken from ):
sed -i "s#enchant_dict_free_suggestions#enchant_dict_free_string_list#g" Source/WebCore/platform/text/enchant/TextCheckerEnchant.cpp
Looks like that API has been around since at least 2005, so it should be no problem to switch.
Really glad that enchant is maintained again.
Committed r222130: <http://trac.webkit.org/changeset/222130>