+AC_CANONICAL_HOST
+case "$host" in
+*-*-darwin* )
+ AC_DEFINE([PURGE_COMMAND],["purge"], [Command to purge filesystem cache])
+ ;;
+*-*-linux* )
+ AC_DEFINE([DROP_CACHE_FILE],["/proc/sys/vm/drop_caches"],
+ [Path to filesystem cache purge interface])
+ ;;
+esac