-dnl /* libvolume_id version */
-VOLID_LT_CURRENT=0
-VOLID_LT_REVISION=86
-VOLID_LT_AGE=0
-AC_SUBST(VOLID_LT_CURRENT)
-AC_SUBST(VOLID_LT_REVISION)
-AC_SUBST(VOLID_LT_AGE)
+dnl /* prefix is /usr, exec_prefix is /, if overridden exec_prefix follows prefix */
+AC_PREFIX_DEFAULT([/usr])
+test "$prefix" = NONE && test "$exec_prefix" = NONE && exec_prefix=
+
+dnl /* libudev version */
+LIBUDEV_LT_CURRENT=4
+LIBUDEV_LT_REVISION=0
+LIBUDEV_LT_AGE=4
+AC_SUBST(LIBUDEV_LT_CURRENT)
+AC_SUBST(LIBUDEV_LT_REVISION)
+AC_SUBST(LIBUDEV_LT_AGE)