Function:    EGAthere()

               This function can be used to test for the
               presence of an EGA or a VGA adaptor. The
               functions relating to specific EGA/VGA routines
               should ensure that an EGA or a VGA is present
               by using this function. Note that this function
               does not differentiate between EGA and VGA,
               test for specific VGA presence with the
               VGAthere() function.

  Syntax:      EGAthere()

  Arguments:   None.

  Returns:     A logical value, .t. when an EGA or a VGA was
               found.

  Usage:       if .not. EGAthere()
                    ? 'Sorry, only EGA/VGA allowed here..'
                    quit
               endif