/* $DOC$
   $NAME$
      ft_DosVer()
   $CATEGORY$
      DOS/BIOS
   $ONELINER$
      Return the current DOS major and minor version as a string
   $SYNTAX$
      ft_DosVer() -> <cVersion>
   $ARGUMENTS$
      None
   $RETURNS$
      A character string with the major version number first, a
      period ("."), then the minor version number (e.g., "3.30")
   $DESCRIPTION$
      ft_DosVer() invokes DOS interrupt 21h, service 30 in order to
      return the current DOS version.  It does this by setting up
      an array corresponding to machine registers and then calling
      the toolkit function ft_int86().

      It returns a character string corresponding to the DOS
      version, as follows:  The major version, a period ("."), then
      the minor version.
   $EXAMPLES$
      ? "OS version:", ft_DosVer()
   $END$
 */