Port to 32-bit --with-wide-int

Prefer symbol indexes to struct Lisp_Symbol * casted and then
widened, as the latter had trouble with GCC on Fedora 21 when
configured --with-wide-int and when used in static initializers.
* lib-src/make-docfile.c (write_globals): Define and use symbols like
iQnil (a small integer, like 0) rather than aQnil (an address
constant).
* src/alloc.c (garbage_collect_1, which_symbols):
* src/lread.c (init_obarray):
Prefer builtin_lisp_symbol when it can be used.
* src/dispextern.h (struct image_type.type):
* src/font.c (font_property_table.key):
* src/frame.c (struct frame_parm_table.sym):
* src/keyboard.c (scroll_bar_parts, struct event_head):
* src/xdisp.c (struct props.name):
Use the index of a builtin symbol rather than its address.
All uses changed.
* src/lisp.h (TAG_SYMPTR, XSYMBOL_INIT): Remove, replacing with ...
(TAG_SYMOFFSET, SYMBOL_INDEX): ... new macros that deal with
symbol indexes rather than pointers, and which work better on MSB
hosts because they shift right before tagging.  All uses changed.
(DEFINE_LISP_SYMBOL_BEGIN, DEFINE_LISP_SYMBOL_END):
No longer noops on wide-int hosts, since they work now.
(builtin_lisp_symbol): New function.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/dispextern.h b/src/dispextern.h
index 161f252dd39..e9e6f709079 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2906,8 +2906,8 @@ struct redisplay_interface
 
 struct image_type
 {
-  /* A symbol uniquely identifying the image type, e.g., 'jpeg'.  */
-  struct Lisp_Symbol *type;
+  /* Index of a symbol uniquely identifying the image type, e.g., 'jpeg'.  */
+  int type;
 
   /* Check that SPEC is a valid image specification for the given
      image type.  Value is true if SPEC is valid.  */