Remove CPP_PLACEMARKERs
* cppexp.c (lex): Don't handle CPP_PLACEMARKER.
* cpplex.c (_cpp_lex_token): Rename skip_newlines to next_bol
* cpplib.c (skip_rest_of_line, check_eol, cpp_push_buffer):
Similarly.
* cpplib.h: Remove CPP_PLACEMARKER.
(struct lexer_state): Rename skip_newlines to next_bol.
* cppmacro.c (stringify_arg): Don't handle CPP_PLACEMARKER.
Simplify prev_white handling as a result.
(paste_all_tokens): Don't worry about CPP_PLACEMARKERs.
(parse_arg): Empty arguments are now empty, not CPP_PLACEMARKERs.
(parse_args): Similarly. Update argument count tests.
(enter_macro_context): Return 2 to indicate an empty macro.
(replace_args): Don't bother pre-expanding an empty argument.
Handle placemarkers and ## extension during pre-expansion.
(cpp_get_token): Handle empty macro expansions. Don't worry
about CPP_PLACEMARKERs.
(_cpp_create_definition): Empty macros are now empty.
(cpp_macro_defintion): Don't special case empty macros.
* scan-decls.c: Don't bother with CPP_PLACEMARKERs.
* c-lex.c: Similarly.
From-SVN: r37385