I made the following changes in order to have observer.[hc] built
in GDB. 

Since this unit is currently unused in GDB, I have considered not
linking in this observer.o. However, I think I've seen another recent
patch that is just about ready to benefit from this framework. So I
discarded this idea.

There is one variable that I don't quite understand; it's
HFILES_NO_SRCDIR. The comment ("Header files that need to have srcdir
added", sic) did not help me, so I wasn't sure that observer.h does
not need to be added to this list. Let me know if it should.

2003-02-27  J. Brobecker  <brobecker@gnat.com>

        * Makefile.in: Add rules to build and link in observer.o.

Ok to apply?
-- 
Joel