This is a small, fast and slightly portable implementation of MGR's
bitblit library for monochrome PC video cards under Linux, derived from
MINIX gas blit.

There are preparations for bitplane colour modes, but these still would
need quite some work to be usable with MGR.

Functions are supplied for opening and closing the screen device, as
well as graphic operations like point and line drawing and
bit-block-transfers, aka as bitblit's.

The basic data structure for this library is a 'BITMAP' as defined
in bitmap.h.  This is a rectangular portion of the screen, some kind
of window, but can also be in memory.

Lots of Authors, Thomas Heller, Dan McCrackin and Alex Liu being three.

The following BLITLIBFLAGS can be used:

  NEED_ADJUST   if your video memory isn't a simple framebuffer like HGC.
                Currently NEED_ADJUST only supports HGC, no other
                "interlaced" cards.

The following SCREEN types can be used:

  hgc           Hercules, also set -DNEED_ADJUST
  vga           VGA

On VGA, MGR will use 640x480 as default.  It supports the following
modes:

	640x200		640x350		640x480 (default)

Trident only:

	800x600		1024x768 (*)	768x1024 (*)

*: Untested.  They seem to run but my monitor won't support those
resolutions.  Please test them out and tell me if they work or not.

For the last three resolutions, you must create three header files

	800x600.h - defintions for 800x600 mode.
	1024x768.h - definitions for the 1024x768 mode.
	768x1024.h - definitions for 768x1024 mode.

This is done with the vgaregs program, which directory also contains
instructions how to use it.

The current dealing with vts is more a hack.  More work should be done
to support switching between vts!

Michael
