Prevent error caused by trying to add a posting for an empty term (created by unac on really weird data)

src/rcldb/rcldb.cpp

@@ -677,6 +677,10 @@ public:
 	// and remember relative.
 	m_ts->curpos = pos;
 	pos += m_ts->basepos;
+	// Don't try to add empty term Xapian doesnt like it... Safety check
+	// this should not happen.
+	if (term.empty())
+	    return true;
 	string ermsg;
 	try {
 	    // Index without prefix, using the field-specific weighting

src/rcldb/termproc.h

@@ -131,6 +131,13 @@ public:
 	    }
 	    return true;
 	}
+	// It may happen in some weird cases that the output from unac is 
+	// empty (if the word actually consisted entirely of diacritics ...)
+	// The consequence is that a phrase search won't work without addional
+	// slack. 
+	if (otrm.empty())
+	    return true;
+	else
 	    return TermProc::takeword(otrm, pos, bs, be);
     }