cpphash.c (_cpp_make_hashnode): Rename make_HASHNODE, now static.
* cpphash.c (_cpp_make_hashnode): Rename make_HASHNODE, now
static. Allocate the hashnode and its string in the same
block of memory.
(del_HASHNODE): Don't free h->name.
(_cpp_lookup): If there is no entry for this string, create
one, of type T_VOID.
(_cpp_lookup_slot): Delete.
* cpphash.h: Update prototypes.
* cpplex.c (maybe_macroexpand): Check for hp->type == T_VOID,
not hp == NULL.
* cpplib.c (do_define, do_undef, do_pragma_poison, do_assert,
do_unassert, cpp_defined): Use _cpp_lookup. Don't create a
node here, just fill in the value field properly. "Delete"
entries by setting the value field to T_VOID. Check for
hp->type == T_VOID, not hp == NULL.
* Makefile.in (cpplib.o): Don't depend on $(HASHTAB_H).
* cpperror.c, cppexp.c, cpplex.c, cpplib.c: Don't include
hashtab.h.