diff -ru -x '*~' udunits-2.1.24_orig/configure udunits-2.1.24/configure
--- udunits-2.1.24_orig/configure	2011-09-13 05:58:39.000000000 +0900
+++ udunits-2.1.24/configure	2014-11-21 21:59:30.308180814 +0900
@@ -7033,7 +7033,7 @@
   ac_status=$?
   $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; then
-    case `/usr/bin/file conftest.o` in
+    case `$MAGIC_CMD conftest.o` in
     *32-bit*)
       case $host in
         x86_64-*kfreebsd*-gnu)