build fixes for AMD64.
Made shm* functions in the libc_wrapper more standard conformant by setting
errno correctly.
Use xf86ExendedInitInt10() in VBEExtendedInit() to be able to pass flags.
IA64 (Egbert Eich).
Fixed wrong function prototype (Egbert Eich).
Don't test for generic VGA on IA64 (Egbert Eich).
Fixed a segfault when accessing a structure before verifying the pointer
exists (Egbert Eich).
Added a showcache option for debugging (Egbert Eich).
Increase default video RAM size to 16MB when DRI is enabled and more than
128MB are available (Egbert Eich). Fixed lockups during mode switch.
Problem was introduced when attempting to copy the behavior during
LeaveVT()/EnterVT() but but forgetting to call I810DRILeave() before
I810DRIEnter(). The entire DRILeave()/Enter() scenario has been
commented out as it didn't seem to be necessary (Egbert Eich).
Fix TweakMemorySize() (tested with i855/i865) (Egbert Eich).
increased MAX_DEVICES to 128 (Egbert Eich).
Use OS provided PCI config space access as default method (Egbert Eich).
Added support for Linux 2.6 proc file format.
Fixed unaligned accesses to pieces of the VBE info block. VESA did not
align elements to size (Egbert Eich).
