Port of the svgalib to RTEMS

Very few changes were needed to get the "drawing backend" working.
All code related with keyboard handling, mouse and joystick has been
removed all commented out.

Major changes:

  + removed mmap() stuff;
  + removed terminal switching
  + removed mouse, keyboard and joystick support
  + chipset support for Trident adn S3 + RAMDAC. 

Demos, vgatest.c, testlinear.c and testgl.c were ported to help to check 
if things are working fine.

Hopefully, this would help people porting GUIs to RTEMS.

Building the library

 + Make sure to localize your cross-compiler settings and RTEMS location in the 
   file "make_include.rtems". The macros that needs to be adjusted are:

       RTEMS_BUILD   = /opt/rtems/
       CROSS_COMPILE = i386-rtems-

 + Call "make" -- this should build the libraries ( libvgva.a and libvgagl.a )
   and the demos. Built svgalib by invoking make:

      make
      make install

 + Using Grub or Netboot load "vgatest" to your target, and check 
   which modes are  supported by your video card. 

 + Using Grub or Netboot load "testgl" to your target, and check 
   if the libvgagl.a is working fine.

Enjoy.

Rosimildo da Silva.  ---  rdasilva@connecttel.com
