Patch: avoid crash with gcj -fno-assume-compiled

[Andrew Haley]

Tom Tromey writes:
 > 
 > Index: ChangeLog
 > from  Tom Tromey  <tromey@redhat.com>
 > 	* class.c (make_class_data): Check that super is compiled before
 > 	building class reference to it.

OK.

Andrew.