Change list-length intptr_t to ptrdiff_t

* src/fns.c (list_length, Fsafe_length, Fproper_list_p):
Use ptrdiff_t not intptr_t for accumulator, since result is ptrdiff_t.
This fixes a minor glitch in 2019-01-11T05:35:31!eggert@cs.ucla.edu
where I removed unnecessary overflow checks but forgot to change types.
This change should alter generated code only on oddball platforms where
ptrdiff_t is narrower than intptr_t, e.g., CheriBSD.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/fns.c b/src/fns.c
index f16e3c1921d..c788ea54ec7 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -117,7 +117,7 @@ See Info node `(elisp)Random Numbers' for more details.  */)
 ptrdiff_t
 list_length (Lisp_Object list)
 {
-  intptr_t i = 0;
+  ptrdiff_t i = 0;
   FOR_EACH_TAIL (list)
     i++;
   CHECK_LIST_END (list, list);
@@ -167,7 +167,7 @@ it returns 0.  If LIST is circular, it returns an integer that is at
 least the number of distinct elements.  */)
   (Lisp_Object list)
 {
-  intptr_t len = 0;
+  ptrdiff_t len = 0;
   FOR_EACH_TAIL_SAFE (list)
     len++;
   return make_fixnum (len);
@@ -248,7 +248,7 @@ A proper list is neither circular nor dotted (i.e., its last cdr is nil).  */
        attributes: const)
   (Lisp_Object object)
 {
-  intptr_t len = 0;
+  ptrdiff_t len = 0;
   Lisp_Object last_tail = object;
   Lisp_Object tail = object;
   FOR_EACH_TAIL_SAFE (tail)