This is the preliminary version of the MGR portable bit-blit library.
It once has been tested on a DEC3100, it runs for sure on a Sun3/4 with
monochrome framebuffer.  It is still missing multi plane (color) support
and was written by Stephen A. Uhler (6/18/89).

The following BLITLIBFLAGS can be set:

  INVERT   invert the sense of black and white
  NOCLIP   Don't do clipping on bit-blits
  UNROLL   unroll loops
  
The following BLITLIBOPT can be used:

  0        leave all the templates intact
  1        expand the switches
  12       expand the bitblt templates
  123      expand the inner loops
  1234     expand the bit shifts
  12345    expand the bitwise operators
  %        Normal CPP defines/includes
#          These always get expanded on the first pass

There are two test programs to make sure that the blit library works:

- rops <min_size> <max_size> <count>
  runs a bunch of random bit-blts

- test_rop <size>
  tests the 16 transfer functions
