qemu-option: Allow deleting opts during qemu_opts_foreach()

Use QTAILQ_FOREACH_SAFE() so that the current QemuOpts can be deleted
while iterating through the whole list.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211008133442.141332-11-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

util/qemu-option.c

@@ -1126,11 +1126,11 @@ int qemu_opts_foreach(QemuOptsList *list, qemu_opts_loopfunc func,
                       void *opaque, Error **errp)
 {
     Location loc;
-    QemuOpts *opts;
+    QemuOpts *opts, *next;
     int rc = 0;
 
     loc_push_none(&loc);
-    QTAILQ_FOREACH(opts, &list->head, next) {
+    QTAILQ_FOREACH_SAFE(opts, &list->head, next, next) {
         loc_restore(&opts->loc);
         rc = func(opaque, opts, errp);
         if (rc) {