Move OVERRIDE/FINAL from gcc/coretypes.h to include/ansidecl.h

Move OVERRIDE/FINAL from gcc/coretypes.h to include/ansidecl.h

So that GDB and other projects that share the top level can use them.

Bootstrapped with all default languages + jit on x86-64 Fedora 23.

gcc/ChangeLog:
2016-10-14  Pedro Alves  <palves@redhat.com>

	* coretypes.h (OVERRIDE, FINAL): Delete, moved to
	include/ansidecl.h.

include/ChangeLog:
2016-10-14  Pedro Alves  <palves@redhat.com>

	* ansidecl.h (GCC_FINAL): Delete.
	(OVERRIDE, FINAL): New, moved from gcc/coretypes.h.