Clean up pthread_create() error handling

Normally pthread_create() rarely fails. But with new pthreads wrapper,
pthread_create() will return ENOSYS on a system without thread support.

Threaded code _is_ protected by HAVE_THREADS and pthread_create()
should never run in the first place. But the situation could change in
the future and bugs may sneak in. Make sure that all pthread_create()
reports the error cause.

While at there, mark these strings for translation if they aren't.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

name-hash.c

@@ -494,6 +494,7 @@ static inline void lazy_update_dir_ref_counts(
 static void threaded_lazy_init_name_hash(
 	struct index_state *istate)
 {
+	int err;
 	int nr_each;
 	int k_start;
 	int t;
@@ -526,8 +527,9 @@ static void threaded_lazy_init_name_hash(
 		if (k_start > istate->cache_nr)
 			k_start = istate->cache_nr;
 		td_dir_t->k_end = k_start;
-		if (pthread_create(&td_dir_t->pthread, NULL, lazy_dir_thread_proc, td_dir_t))
-			die("unable to create lazy_dir_thread");
+		err = pthread_create(&td_dir_t->pthread, NULL, lazy_dir_thread_proc, td_dir_t);
+		if (err)
+			die(_("unable to create lazy_dir thread: %s"), strerror(err));
 	}
 	for (t = 0; t < lazy_nr_dir_threads; t++) {
 		struct lazy_dir_thread_data *td_dir_t = td_dir + t;
@@ -547,13 +549,15 @@ static void threaded_lazy_init_name_hash(
 	 */
 	td_name->istate = istate;
 	td_name->lazy_entries = lazy_entries;
-	if (pthread_create(&td_name->pthread, NULL, lazy_name_thread_proc, td_name))
-		die("unable to create lazy_name_thread");
+	err = pthread_create(&td_name->pthread, NULL, lazy_name_thread_proc, td_name);
+	if (err)
+		die(_("unable to create lazy_name thread: %s"), strerror(err));
 
 	lazy_update_dir_ref_counts(istate, lazy_entries);
 
-	if (pthread_join(td_name->pthread, NULL))
-		die("unable to join lazy_name_thread");
+	err = pthread_join(td_name->pthread, NULL);
+	if (err)
+		die(_("unable to join lazy_name thread: %s"), strerror(err));
 
 	cleanup_dir_mutex();
 

preload-index.c

@@ -121,6 +121,8 @@ static void preload_index(struct index_state *index,
 
 	for (i = 0; i < threads; i++) {
 		struct thread_data *p = data+i;
+		int err;
+
 		p->index = index;
 		if (pathspec)
 			copy_pathspec(&p->pathspec, pathspec);
@@ -129,8 +131,10 @@ static void preload_index(struct index_state *index,
 		if (pd.progress)
 			p->progress = &pd;
 		offset += work;
-		if (pthread_create(&p->pthread, NULL, preload_thread, p))
-			die("unable to create threaded lstat");
+		err = pthread_create(&p->pthread, NULL, preload_thread, p);
+
+		if (err)
+			die(_("unable to create threaded lstat: %s"), strerror(err));
 	}
 	for (i = 0; i < threads; i++) {
 		struct thread_data *p = data+i;

run-command.c

@@ -1213,7 +1213,7 @@ int start_async(struct async *async)
 	{
 		int err = pthread_create(&async->tid, NULL, run_thread, async);
 		if (err) {
-			error_errno("cannot create thread");
+			error(_("cannot create async thread: %s"), strerror(err));
 			goto error;
 		}
 	}