diff -burN crack-0.4.orig/config.m4 crack-0.4/config.m4
--- crack-0.4.orig/config.m4	2005-09-05 15:23:35.874777736 +0200
+++ crack-0.4/config.m4	2005-09-05 15:23:59.894126240 +0200
@@ -10,7 +10,7 @@
   if test "$PHP_CRACK" != "yes"; then
     AC_MSG_ERROR(Only the bundled library is supported right now)
     
-    for i in $PHP_CRACK/lib $PHP_CRACK/cracklib /usr/local/lib /usr/lib; do
+    for i in $PHP_CRACK/lib $PHP_CRACK/cracklib /usr/local/lib /usr/lib /usr/lib64; do
       test -f $i/libcrack.$SHLIB_SUFFIX_NAME -o -f $i/libcrack.a && CRACK_LIBDIR=$i && break
     done