Copy name in LoadDictionary if not dictionary_name

compiledict.c sets dict_name to dictionary_name if dict_name is
not set, and passes that to LoadDictionary. LoadDictionary then
copies the passed in name to dictionary_name.

This causes -fsanitize=address to fail with overlapping memory
addresses passed to strncpy (copying the string to itself). As
such, don't copy the name in this case.

src/libespeak-ng/dictionary.c

 	int size;
 	char fname[sizeof(path_home)+20];
 
-	strncpy(dictionary_name, name, 40); // currently loaded dictionary name
+	if (dictionary_name != name)
+		strncpy(dictionary_name, name, 40); // currently loaded dictionary name
 	strncpy(tr->dictionary_name, name, 40);
 
 	// Load a pronunciation data file into memory