add s_utf8.h header to s_path.c

pd/src/s_path.c

@@ -27,6 +27,7 @@
 #include "m_pd.h"
 #include "m_imp.h"
 #include "s_stuff.h"
+#include "s_utf8.h"
 #include <stdio.h>
 #include <fcntl.h>
 #include <ctype.h>