MINOR: init/threads: remove the useless tids[] array

It's still obscure how we managed to initialize an array of integers
with values always equal to the index, just to retrieve the value
from an opaque pointer to the index instead of directly using it! I
suspect it's a leftover from the very early threading experiments.

This commit gets rid of this and simply passes the thread ID as the
argument to run_thread_poll_loop(), thus significantly simplifying the
few call places and removing the need to allocate then free an array
of identity.
diff --git a/src/haproxy.c b/src/haproxy.c
index 1aeae99..43b2118 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -690,7 +690,7 @@
 		leave */
 
 	fork_poller();
-	run_thread_poll_loop((int []){0});
+	run_thread_poll_loop(0);
 }
 
 /*
@@ -2492,7 +2492,7 @@
 	struct per_thread_deinit_fct *ptdf;
 	__decl_hathreads(static HA_SPINLOCK_T start_lock);
 
-	ha_set_tid(*((unsigned int *)data));
+	ha_set_tid((unsigned long)data);
 	tv_update_date(-1,-1);
 
 	list_for_each_entry(ptif, &per_thread_init_list, list) {
@@ -3125,15 +3125,10 @@
 	 */
 #ifdef USE_THREAD
 	{
-		unsigned int *tids    = calloc(global.nbthread, sizeof(unsigned int));
 		pthread_t    *threads = calloc(global.nbthread, sizeof(pthread_t));
 		int          i;
 		sigset_t     blocked_sig, old_sig;
 
-		/* Init tids array */
-		for (i = 0; i < global.nbthread; i++)
-			tids[i] = i;
-
 		/* ensure the signals will be blocked in every thread */
 		sigfillset(&blocked_sig);
 		sigdelset(&blocked_sig, SIGPROF);
@@ -3146,7 +3141,7 @@
 		/* Create nbthread-1 thread. The first thread is the current process */
 		threads[0] = pthread_self();
 		for (i = 1; i < global.nbthread; i++)
-			pthread_create(&threads[i], NULL, &run_thread_poll_loop, &tids[i]);
+			pthread_create(&threads[i], NULL, &run_thread_poll_loop, (void *)(long)i);
 
 #ifdef USE_CPU_AFFINITY
 		/* Now the CPU affinity for all threads */
@@ -3180,13 +3175,12 @@
 		haproxy_unblock_signals();
 
 		/* Finally, start the poll loop for the first thread */
-		run_thread_poll_loop(&tids[0]);
+		run_thread_poll_loop(0);
 
 		/* Wait the end of other threads */
 		for (i = 1; i < global.nbthread; i++)
 			pthread_join(threads[i], NULL);
 
-		free(tids);
 		free(threads);
 
 #if defined(DEBUG_THREAD) || defined(DEBUG_FULL)
@@ -3195,8 +3189,7 @@
 	}
 #else /* ! USE_THREAD */
 	haproxy_unblock_signals();
-	run_thread_poll_loop((int []){0});
-
+	run_thread_poll_loop(0);
 #endif
 
 	/* Do some cleanup */