Trouble when mkdb-ing with ORBit-generated headers

[Federico Mena Quintero <federico ximian com>]

If I gtkdoc-mkdb for evolution/calendar/cal-client/, it screams that
evolution-calendar.h has unparsable comments.  However, that file is
generated by orbit-idl and really does not need to be scanned.

It seems that gtkdoc-mkdb is reading all the .h files in the
directory by itself; is there a way to specify which ones to ignore?
It doesn't seem to have an --ignore-blah option.

  Federico