Problem with msdos86 and msdos386 targets

[johnsonjh]

See https://github.com/johnsonjh/pcdos-crc (or https://GitLab.com/dps8m/crc).

This program currently works on over 50 different compilers on nearly 30 tested platforms, however, Ack targeting msdos86/msdos386 does not work, it seems to miscompile somehow and always shows a 0 CRC.

I didn’t investigate much further, however the UNIX V7 and CP/M-80 Ack builds have been fully tested and work correctly.

[johnsonjh]

It looks like "rb" is broken:

• test.c:

  #include <stdio.h>
  
  int main(void)
  {
    FILE * fp1 = fopen ("test.c", "r");
    FILE * fp2 = fopen ("test.c", "rb");
  
    printf (" r=%d\n", fgetc (fp1));
    printf ("rb=%d\n", fgetc (fp2));
  
    return 0;
  }

• Result:

  $ /opt/ack/bin/ack -mmsdos86 -O3 test.c -o test.com
  $ emu2 test.com
   r=35
  rb=-1

[johnsonjh]

@davidgiven I fixed it - PR coming.

[johnsonjh]

@davidgiven #366 fixes the problem - binary mode file I/O was broken, it was always returning EOF and never what was read.