Yeah, it's a bummer but mkgmap doesn't keep track of what options are
valid - the options are detected in whatever part of the code is
interested in them but if you specify a bad option name, nothing
notices. Should be fixed.
It would really be great if mkgmap checked whether an option is
actually used or not and if you give a wrong option or say
--style-file=test1 but test1 not existing it should not default to
default values but complain about wrong option used. This would be much
more beginner friendly.