Make struct Lisp_Objfwd etc. objects read-only

Initialize these objects statically, and make them constants.
This is a bit safer and more efficient.
* src/data.c (XBOOLFWD, XKBOARD_OBJFWD, XFIXNUMFWD, XOBJFWD):
* src/lisp.h (XBUFFER_OBJFWD):
Return a pointer-to-const instead of an unrestricted pointer.
(lispfwd): fwdptr is now a pointer-to-const instead of an
unrestricted pointer.  All uses changed.
(SET_SYMBOL_FWD): Accept pointer-to-const instead of an
unrestricted pointer.
(DEFVAR_LISP, DEFVAR_LISP_NOPRO, DEFVAR_BOOL, DEFVAR_INT)
(DEFVAR_KBOARD): Initialize static structures statically
instead of dynamically, and make them const.
* src/lread.c (defvar_int, defvar_bool, defvar_lisp_nopro)
(defvar_lisp, defvar_kboard): Accept pointer-to-const instead
of an unrestricted pointer; it’s now the caller’s
responsibility to initialize the pointed-to storage.  No need
for a separate address argument any more.  All callers
changed.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/data.c b/src/data.c
index 936bb74f69a..11cd598ed85 100644
--- a/src/data.c
+++ b/src/data.c
@@ -62,25 +62,25 @@ OBJFWDP (lispfwd a)
   return XFWDTYPE (a) == Lisp_Fwd_Obj;
 }
 
-static struct Lisp_Boolfwd *
+static struct Lisp_Boolfwd const *
 XBOOLFWD (lispfwd a)
 {
   eassert (BOOLFWDP (a));
   return a.fwdptr;
 }
-static struct Lisp_Kboard_Objfwd *
+static struct Lisp_Kboard_Objfwd const *
 XKBOARD_OBJFWD (lispfwd a)
 {
   eassert (KBOARD_OBJFWDP (a));
   return a.fwdptr;
 }
-static struct Lisp_Intfwd *
+static struct Lisp_Intfwd const *
 XFIXNUMFWD (lispfwd a)
 {
   eassert (INTFWDP (a));
   return a.fwdptr;
 }
-static struct Lisp_Objfwd *
+static struct Lisp_Objfwd const *
 XOBJFWD (lispfwd a)
 {
   eassert (OBJFWDP (a));