* cpphash.h: (TOKEN_SPELL) Pulled from cpplex.c.
* cpplex.c (TOKEN_SPELL) Move to cpphash.h.
* cpphash.c: (struct macro_info, alloc_macro, free_macro,
struct toklist_dummy): New.
(cpp_free_definition): Free macros with free_macro.
(count_params): Don't save paramter spellings. Save macro
information in a struct macro_info.
(parse_define): Don't allocate a token list.
(save_expansion): Allocate the macro's token list, and
save parameter spellings if necessary. Use TOKEN_SPELL.
(cpp_create_definition): Make list const.