[PATCH v1 4/4] compat/obstack: fix some sparse warnings

["SZEDER Gábor" <szeder.dev@gmail.com>]

'compat/obstack.c' occasionally assigns/compares a plain 0 to a
pointer, which triggers sparse warnings.  Use NULL instead.

This is basically a cherry-pick of 3254310863 (obstack.c: Fix some
sparse warnings, 2011-09-11) on top of the just updated code from
upstream.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
---
 compat/obstack.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/compat/obstack.c b/compat/obstack.c
index 6ef8cecb8a..5fff087cd3 100644
--- a/compat/obstack.c
+++ b/compat/obstack.c
@@ -135,7 +135,7 @@ _obstack_begin_worker (struct obstack *h,
   h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
                                                alignment - 1);
   h->chunk_limit = chunk->limit = (char *) chunk + h->chunk_size;
-  chunk->prev = 0;
+  chunk->prev = NULL;
   /* The initial chunk now contains no empty object.  */
   h->maybe_empty_object = 0;
   h->alloc_failed = 0;
@@ -178,7 +178,7 @@ void
 _obstack_newchunk (struct obstack *h, _OBSTACK_SIZE_T length)
 {
   struct _obstack_chunk *old_chunk = h->chunk;
-  struct _obstack_chunk *new_chunk = 0;
+  struct _obstack_chunk *new_chunk = NULL;
   size_t obj_size = h->next_free - h->object_base;
   char *object_base;
 
@@ -243,12 +243,12 @@ _obstack_allocated_p (struct obstack *h, void *obj)
   /* We use >= rather than > since the object cannot be exactly at
      the beginning of the chunk but might be an empty object exactly
      at the end of an adjacent chunk.  */
-  while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
+  while (lp != NULL && ((void *) lp >= obj || (void *) (lp)->limit < obj))
     {
       plp = lp->prev;
       lp = plp;
     }
-  return lp != 0;
+  return lp != NULL;
 }
 
 /* Free objects in obstack H, including OBJ and everything allocate
@@ -264,7 +264,7 @@ _obstack_free (struct obstack *h, void *obj)
   /* We use >= because there cannot be an object at the beginning of a chunk.
      But there can be an empty object at that address
      at the end of another chunk.  */
-  while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
+  while (lp != NULL && ((void *) lp >= obj || (void *) (lp)->limit < obj))
     {
       plp = lp->prev;
       call_freefun (h, lp);
@@ -279,7 +279,7 @@ _obstack_free (struct obstack *h, void *obj)
       h->chunk_limit = lp->limit;
       h->chunk = lp;
     }
-  else if (obj != 0)
+  else if (obj != NULL)
     /* obj is not in any of the chunks! */
     abort ();
 }
@@ -290,7 +290,7 @@ _obstack_memory_used (struct obstack *h)
   struct _obstack_chunk *lp;
   _OBSTACK_SIZE_T nbytes = 0;
 
-  for (lp = h->chunk; lp != 0; lp = lp->prev)
+  for (lp = h->chunk; lp != NULL; lp = lp->prev)
     {
       nbytes += lp->limit - (char *) lp;
     }
-- 
2.22.0.589.g5bd7971b91