support 64-bit EMACS_INT on 32-bit hosts

[Paul Eggert <eggert@cs.ucla.edu>]

On 04/29/11 01:08, Paul Eggert wrote:

> Step 2 will change EMACS_INT to be 64 bits on 32+64-bit ports.
> That is a bigger deal, and I'll send a later email about it.

Here's a simple patch to do this.  With this patch (atop the previous one),
I've successfully used Emacs to edit a 2 GB file on an x86 (32-bit)
platform.  I've only done very limited testing with this patch,
though, and I don't plan to install this patch right now; it needs
more testing.  However, I thought I'd publish it now as a heads-up.

* lisp.h: Prefer 64-bit EMACS_INT if available.
(EMACS_INT, EMACS_UINT, BITS_PER_EMACS_INT, pI): Define to 64-bit
on 32-bit hosts that have 64-bit int, so that they can access
large files.
=== modified file 'src/lisp.h'
--- src/lisp.h	2011-04-29 07:54:43 +0000
+++ src/lisp.h	2011-04-29 08:48:05 +0000
@@ -44,7 +44,16 @@
 #ifndef EMACS_UINT
 #define EMACS_UINT unsigned long
 #endif
-#else /* not _LP64 */
+#elif /* !_LP64 && */ BITS_PER_LONG < BITS_PER_LONG_LONG
+#ifndef EMACS_INT
+#define EMACS_INT long long
+#define BITS_PER_EMACS_INT BITS_PER_LONG_LONG
+#define pI "ll"
+#endif
+#ifndef EMACS_UINT
+#define EMACS_UINT unsigned long long
+#endif
+#else /* ! (_LP64 || BITS_PER_LONG < BITS_PER_LONG_LONG) */
 #ifndef EMACS_INT
 #define EMACS_INT int
 #define BITS_PER_EMACS_INT BITS_PER_INT