bmp2c64: use binary stdout on win32

this preserves unix-style EOL
allow building all on win32, with MinGW installed

- provide a simple getopt implementation for cc1541.c, taken from the net
  and slightly modified to work for this purpose
- avoid 'echo' in Makefile, as not to create windows line endings
- use variables in Makefile to make up for different shell syntax of
  bourne shell and win32 command line