Add init function support to tsd members.

This will facilitate embedding tcache into tsd, which will require proper
initialization cannot be done via the static initializer.  Make tsd->rtree_ctx
to be initialized via rtree_ctx_data_init().

src/rtree.c

@@ -424,3 +424,14 @@ rtree_leaf_elm_witness_release(tsdn_t *tsdn, const rtree_t *rtree,
 	witness_unlock(tsdn, witness);
 	rtree_leaf_elm_witness_dalloc(tsdn_tsd(tsdn), witness, elm);
 }
+
+bool
+rtree_ctx_data_init(rtree_ctx_t *ctx) {
+	for (unsigned i = 0; i < RTREE_CTX_NCACHE; i++) {
+		rtree_ctx_cache_elm_t *cache = &ctx->cache[i];
+		cache->leafkey = RTREE_LEAFKEY_INVALID;
+		cache->leaf = NULL;
+	}
+
+	return false;
+}

src/tsd.c

@@ -60,6 +60,23 @@ malloc_tsd_cleanup_register(bool (*f)(void)) {
 	ncleanups++;
 }
 
+bool
+tsd_data_init(void *arg) {
+	tsd_t *tsd = (tsd_t *)arg;
+#define MALLOC_TSD_init_yes(n, t)					\
+	if (n##_data_init(&tsd->n)) {					\
+		return true;						\
+	}
+#define MALLOC_TSD_init_no(n, t)
+#define O(n, t, gs, i, c)						\
+	MALLOC_TSD_init_##i(n, t)
+MALLOC_TSD
+#undef MALLOC_TSD_init_yes
+#undef MALLOC_TSD_init_no
+#undef O
+	return false;
+}
+
 void
 tsd_cleanup(void *arg) {
 	tsd_t *tsd = (tsd_t *)arg;
@@ -72,7 +89,7 @@ tsd_cleanup(void *arg) {
 #define MALLOC_TSD_cleanup_yes(n, t)					\
 		n##_cleanup(tsd);
 #define MALLOC_TSD_cleanup_no(n, t)
-#define O(n, t, gs, c)							\
+#define O(n, t, gs, i, c)						\
 		MALLOC_TSD_cleanup_##c(n, t)
 MALLOC_TSD
 #undef MALLOC_TSD_cleanup_yes