Add HAVE_STRVERSCMP, guard the only usage of strverscmp with #ifdef

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

coreutils/ls.c

@@ -886,9 +886,11 @@ static int sortcmp(const void *a, const void *b)
 	if (sort_opts == SORT_DIR) {
 		dif = S_ISDIR(d2->dn_mode) - S_ISDIR(d1->dn_mode);
 	} else
+#ifdef HAVE_STRVERSCMP && HAVE_STRVERSCMP == 1
 	if (sort_opts == SORT_VERSION) {
 		dif = strverscmp(d1->name, d2->name);
 	} else
+#endif
 	if (sort_opts == SORT_EXT) {
 		dif = strcmp(strchrnul(d1->name, '.'), strchrnul(d2->name, '.'));
 	}