Provide access to scratch in queues

This largely reverts commit f8ecf33236b0695d9539e8e34cf0bb0467614cdf.

src/nfa/nfa_api_queue.h

@@ -91,6 +91,7 @@ struct mq {
                         * history buffer; (logically) immediately before the
                         * main buffer */
     size_t hlength; /**< length of the history buffer */
+    struct hs_scratch *scratch; /**< global scratch space */
     char report_current; /**<
                           * report_current matches at starting offset through
                           * callback. If true, the queue must be located at a

src/scratch.c

@@ -227,6 +227,11 @@ hs_error_t alloc_scratch(const hs_scratch_t *proto, hs_scratch_t **scratch) {
     // Don't get too big for your boots
     assert((size_t)(current - (char *)s) <= alloc_size);
 
+    // Init q->scratch ptr for every queue.
+    for (struct mq *qi = s->queues; qi != s->queues + queueCount; ++qi) {
+        qi->scratch = s;
+    }
+
     return HS_SUCCESS;
 }