Allow gap before first non-Lisp pseudovec member

Problem reported by Keith David Bershatsky in:
https://lists.gnu.org/r/emacs-devel/2019-04/msg00259.html
Solution suggested by Stefan Monnier in:
https://lists.gnu.org/r/emacs-devel/2019-04/msg00282.html
* src/buffer.h (BUFFER_LISP_SIZE): Simplify by using PSEUDOVECSIZE.
(BUFFER_REST_SIZE): Simplify by using VECSIZE and BUFFER_LISP_SIZE.
* src/lisp.h (PSEUDOVECSIZE): Base it on the last Lisp field,
not the first non-Lisp field.  All callers changed.  Callers
without Lisp fields changed to use ALLOCATE_PLAIN_PSEUDOVECTOR.
(ALLOCATE_PLAIN_PSEUDOVECTOR): New macro.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/bignum.c b/src/bignum.c
index 4118601e108..009d73118c2 100644
--- a/src/bignum.c
+++ b/src/bignum.c
@@ -86,8 +86,8 @@ make_bignum_bits (size_t bits)
   if (integer_width < bits)
     overflow_error ();
 
-  struct Lisp_Bignum *b = ALLOCATE_PSEUDOVECTOR (struct Lisp_Bignum, value,
-                                                 PVEC_BIGNUM);
+  struct Lisp_Bignum *b = ALLOCATE_PLAIN_PSEUDOVECTOR (struct Lisp_Bignum,
+                                                       PVEC_BIGNUM);
   mpz_init (b->value);
   mpz_swap (b->value, mpz[0]);
   return make_lisp_ptr (b, Lisp_Vectorlike);
@@ -342,8 +342,8 @@ bignum_to_string (Lisp_Object num, int base)
 Lisp_Object
 make_bignum_str (char const *num, int base)
 {
-  struct Lisp_Bignum *b = ALLOCATE_PSEUDOVECTOR (struct Lisp_Bignum, value,
-                                                 PVEC_BIGNUM);
+  struct Lisp_Bignum *b = ALLOCATE_PLAIN_PSEUDOVECTOR (struct Lisp_Bignum,
+                                                       PVEC_BIGNUM);
   mpz_init (b->value);
   int check = mpz_set_str (b->value, num, base);
   eassert (check == 0);