make: use the more modern wchar routines, not widec.h

@@ -495,11 +495,11 @@
                         str.init(p);
                         wchar_t * wcb = str.get_string();
                         if ((p->colons != no_colon) &&
                             ((wcb[0] != (int) period_char) ||
                              ((wcb[0] == (int) period_char) &&
-                              (wschr(wcb, (int) slash_char))))) {
+                              (wcschr(wcb, (int) slash_char))))) {
                                 print_target_n_deps(p);
                         }
         }
 }