FcLangSetHasLang - test langset for language support
#include <fontconfig/fontconfig.h>
FcLangResult FcLangSetHasLang (const FcLangSet *ls, const FcChar8 *lang);
FcLangSetHasLang checks whether ls supports
lang. If ls has a matching language and territory pair, this
function returns FcLangEqual. If ls has a matching language but
differs in which territory that language is for, this function returns
FcLangDifferentTerritory. If ls has no matching language, this
function returns FcLangDifferentLang.