Jd>  Interesting, that.  Everyone else (most MAKE utilities, and most
 Jd>  programs that allow you to "shell out") uses COMSPEC. 
Even CMD uses
 Jd>  COMSPEC, to determine what shell to start for the START and DETACH
 Jd>  commands when an internal command or batch file is specified.

 Jd>  The only people that I've encountered that use OS2_SHELL are Borland,
 Jd>  and now you.

I tried to cover all the bases:

  char *env;

  env = getenv("COMSPEC");
  if(!env)
    env = getenv("OS2_SHELL");
  if(!env)
    env = "CMD.EXE";

--- XHEd-OS/2 1.22