Fix aborts in GC under GC_CHECK_MARKED_OBJECTS

* src/alloc.c (mark_object) [GC_CHECK_MARKED_OBJECTS]: Don't abort
for thread objects.  They are marked via the all_threads list, and
therefore don't need to be inserted into the red-black tree, so
mem_find will never find them.  Reported by Daniel Colascione
<dancol@dancol.org> in
http://lists.gnu.org/archive/html/emacs-devel/2016-12/msg00817.html.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/alloc.c b/src/alloc.c
index f2b7682b05d..e979f3631ee 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -6406,7 +6406,7 @@ mark_object (Lisp_Object arg)
 
 #ifdef GC_CHECK_MARKED_OBJECTS
         m = mem_find (po);
-        if (m == MEM_NIL && !SUBRP (obj))
+        if (m == MEM_NIL && !SUBRP (obj) && !THREADP (obj))
           emacs_abort ();
 #endif /* GC_CHECK_MARKED_OBJECTS */
 
@@ -6416,7 +6416,9 @@ mark_object (Lisp_Object arg)
         else
           pvectype = PVEC_NORMAL_VECTOR;
 
-        if (pvectype != PVEC_SUBR && pvectype != PVEC_BUFFER)
+        if (pvectype != PVEC_SUBR
+            && pvectype != PVEC_BUFFER
+            && pvectype != PVEC_THREAD)
           CHECK_LIVE (live_vector_p);
 
         switch (pvectype)