Adds support to collection using memcache.

This is the initial support to collections using memcache.

apache2/msc_persistent_memcache.h

@@ -0,0 +1,30 @@
+/*
+* ModSecurity for Apache 2.x, http://www.modsecurity.org/
+* Copyright (c) 2004-2013 Trustwave Holdings, Inc. (http://www.trustwave.com/)
+*
+* You may not use this file except in compliance with
+* the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* If any of the files related to licensing are missing or if you have any
+* other questions related to licensing please contact Trustwave Holdings, Inc.
+* directly using the email address security@modsecurity.org.
+*/
+
+#ifndef _PERSIST_MEMCACHE_H_
+#define _PERSIST_MEMCACHE_H_
+
+#include "apr_general.h"
+#include "modsecurity.h"
+
+apr_table_t DSOLOCAL *msc_memcache_collection_retrieve(modsec_rec *msr,
+	const char *col_name, const char *col_value, int col_value_length);
+
+int DSOLOCAL msc_memcache_collection_store(modsec_rec *msr,
+	apr_table_t *collection);
+
+int DSOLOCAL msc_memcache_collections_remove_stale(modsec_rec *msr,
+	const char *col_name);
+
+#endif