New variable.

New variable.
(INTERVAL_SRC): Convert to make variable.
(INTERVAL_OBJ, MKTIME_OBJ, FLOAT_SUPPORT, FACE_SUPPORT)
(HAVE_X_WINDOWS, OBJECTS_SYSTEM): Remove.
(obj): Substitute INTERVAL_OBJ, add MKTIME_OBJ, GETLOADAVG_OBJ and
@LIBOBJS@.
(SOME_MACHINE_OBJECTS): Remove interval stuff.
(lisp): Substitute FACE_SUPPORT, FLOAT_SUP.
(shortlisp): Add facemenu, float-sup, frame.
(SOME_MACHINE_LISP): Remove them from here.
(LIBES): Change unused LDLIBS to autoconf LIBS.