diff --git a/configure.ac b/configure.ac
index 667126ad03..8ae4fd1d26 100644
--- a/configure.ac
+++ b/configure.ac
@@ -151,8 +151,6 @@ AC_DEFINE_UNQUOTED(AIKSAURUS_H_LOCATION,$lyx_cv_aiksaurus_h_location,[Location o
 fi
 AC_SUBST(AIKSAURUS_LIBS)
 
-AC_DEFINE(HAVE_THESAURUS, (HAVE_LIBMYTHES || HAVE_LIBAIKSAURUS),[Define this if you have a supported thesaurus library])
-
 LYX_USE_INCLUDED_BOOST
 
 # Needed for our char_type
diff --git a/src/LyXFunc.cpp b/src/LyXFunc.cpp
index ee6c942ca6..d52406b395 100644
--- a/src/LyXFunc.cpp
+++ b/src/LyXFunc.cpp
@@ -395,7 +395,7 @@ FuncStatus LyXFunc::getStatus(FuncRequest const & cmd) const
 
 	switch (cmd.action) {
 	case LFUN_UNKNOWN_ACTION:
-#ifndef HAVE_THESAURUS
+#if !defined(HAVE_LIBMYTHES) && !defined(HAVE_LIBAIKSAURUS)
 	case LFUN_THESAURUS_ENTRY:
 #endif
 		flag.unknown(true);