[AD] Allegro on amd64-linux

[Eric Botcazou <ebotcazou@xxxxxxxxxx>]

I've started to toy with Allegro on amd64-linux (Mandrake 10.0).  The library 
doesn't compile on the machine because of undefined references to outportb 
and the likes (reproducible with --disable-vga).  This was broken by Chris' 
09/17 patch (and hinted at by Peter) because the functions are defined only 
if ALLEGRO_LINUX_VGA is but used in the sources if GFX_MODEX is defined..

I think the patch should be reverted.  I think it makes sense to write:

   #ifdef GFX_MODEX

       /* create a nice wide virtual screen, and split it at line 200 */
       if (set_gfx_mode(GFX_MODEX, 320, 240, 640, 240) != 0) {

like in exscroll.c.  Note that split_modex_screen is not compiled when 
--disable-vga is passed to configure so exscroll fails to link.

Once the problem is worked around, the library compiles fine in strictwarn 
mode (GCC 3.3.2):
[eric@xxxxxxxxxx unix]$ file liballeg-4.1.17.so
liballeg-4.1.17.so: ELF 64-bit LSB shared object, AMD x86-64, version 1 
(SYSV), stripped

The test program appears to work fine. The demo is more problematic: the FLI 
player doesn't display anything, the sound is broken and the keyboard 
responsiveness is abysmal.

I'll try to investigate in the next few weeks.

-- 
Eric Botcazou