MT#55283 work around gcc <12 being stupid

gcc <12 propagates the const-ness of the given value to the newly
declared variable with __auto_type, leading to silly "can't assign to
const variable" errors. Work around this with an ugly macro.

Change-Id: Ic952c094c24bd802379fc10ad19d559613b2c1d0

daemon/call.c

@@ -1664,7 +1664,7 @@ static void __generate_crypto(const sdp_ng_flags *flags, struct call_media *this
 
 			/* first add those mentioned in the order list,
 			 * but only, if they were previously generated/added to the sdes_out */
-			for (__auto_type l = cpq_order->head; l; l = l->next)
+			for (auto_iter(l, cpq_order->head); l; l = l->next)
 			{
 				str * cs_name = l->data;
 				struct crypto_params_sdes * cps_order;
@@ -1702,7 +1702,7 @@ static void __generate_crypto(const sdp_ng_flags *flags, struct call_media *this
 
 			t_queue_init(offered_cpq); /* re-initialize offered crypto suites */
 
-			for (__auto_type l = offered_order->head; l; l = l->next)
+			for (auto_iter(l, offered_order->head); l; l = l->next)
 			{
 				str * cs_name = l->data;
 				__auto_type elem = t_queue_find_custom(&offered_cpq_orig_list, cs_name, crypto_params_sdes_cmp);
@@ -3326,7 +3326,7 @@ int monologue_subscribe_request(const subscription_q *srms, struct call_monologu
 	__call_monologue_init_from_flags(dst_ml, flags);
 
 	g_auto(GQueue) mls = G_QUEUE_INIT; /* to avoid duplications */
-	for (__auto_type sl = srms->head; sl; sl = sl->next)
+	for (auto_iter(sl, srms->head); sl; sl = sl->next)
 	{
 		struct media_subscription *ms = sl->data;
 		struct call_monologue *src_ml = ms->monologue;

daemon/call_interfaces.c

@@ -2299,7 +2299,7 @@ static void ng_stats_media(bencode_item_t *list, const struct call_media *m,
 	BF_M("generator/sink", GENERATOR);
 
 stats:
-	for (__auto_type l = m->streams.head; l; l = l->next) {
+	for (auto_iter(l, m->streams.head); l; l = l->next) {
 		ps = l->data;
 		ng_stats_stream(streams, ps, totals);
 	}

daemon/codec.c

@@ -5616,7 +5616,7 @@ void codec_store_synthesise(struct codec_store *dst, struct codec_store *opposit
 
 // check all codecs listed in the source are also be present in the answer (dst)
 bool codec_store_is_full_answer(const struct codec_store *src, const struct codec_store *dst) {
-	for (__auto_type l = src->codec_prefs.head; l; l = l->next) {
+	for (auto_iter(l, src->codec_prefs.head); l; l = l->next) {
 		const rtp_payload_type *src_pt = l->data;
 		const rtp_payload_type *dst_pt = t_hash_table_lookup(dst->codecs,
 				GINT_TO_POINTER(src_pt->payload_type));

daemon/sdp.c

@@ -1748,7 +1748,7 @@ int sdp_streams(const sdp_sessions_q *sessions, sdp_streams_q *streams, sdp_ng_f
 	unsigned int num = 0;
 	struct sdp_attribute *attr;
 
-	for (__auto_type l = sessions->head; l; l = l->next) {
+	for (auto_iter(l, sessions->head); l; l = l->next) {
 		session = l->data;
 
 		for (__auto_type k = session->media_streams.head; k; k = k->next) {

include/crypto.h

@@ -218,7 +218,7 @@ INLINE void crypto_params_sdes_queue_clear(sdes_q *q) {
 	t_queue_clear_full(q, crypto_params_sdes_free);
 }
 INLINE void crypto_params_sdes_queue_copy(sdes_q *dst, const sdes_q *src) {
-	for (__auto_type l = src->head; l; l = l->next) {
+	for (auto_iter(l, src->head); l; l = l->next) {
 		struct crypto_params_sdes *cps = l->data;
 		struct crypto_params_sdes *cpy = g_slice_alloc(sizeof(*cpy));
 		*cpy = *cps;

lib/auxlib.h

@@ -81,6 +81,7 @@ int num_cpu_cores(int);
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(char, g_free)
 typedef char *char_p;
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(char_p, g_strfreev)
+#define auto_iter(v, l) __typeof__ ( ({ __typeof__ (*l) __t; &__t; }) ) v = (l) /* for gcc <12 */
 
 
 /*** STRING HELPERS ***/