* cpphash.h: Use HAVE_DESIGNATED_INITIALIZERS.
(_cpp_trigraph_map): Declaration moved from cpplex.c
* cppinit.c: Define _cpp_trigraph_map. Use UCHAR_MAX + 1
instead of 256. Use consistent test for designated initializers.
(cpp_init): Initialize trigraph_map.
(initialize_standard_includes, parse_option): Use memcmp
instead of strncmp.
* cpplex.c (init_trigraph_map): Remove.
(trigraph_ok, trigraph_replace, lex_line): Refer to
_cpp_trigraph_map.