libssp47, libobjc47: install headers

libssp47, libobjc47: install headers

Headers for both libssp and libobjc were not getting installed for the
gcc47 library set.  As an aside, the gcc44 libobjc is also missing these
headers.  There installation required an mtree change, but it can be
built with quickworld.

Additionally, CFLAGS were moved to above an include for libobjc which
should ensure the local config.h is included before a different version
and this in turn likely improves libobjc functionality.