e.g. __REGISTER_PREFIX__.
* cpphash.h (struct cpp_reader): Move member warn_dollars...
* cpplib.h (struct cpp_options): ...to here. Change type to
unsigned char.
* cppinit.c (cpp_create_reader): Set it to 1 here.
(post_options): Don't set it here.
* c-opts.c (c_common_init_options): Reset it to 0 here.
(finish_options): Set it here.
* cpplex.c (forms_identifier_p): Tweak for new location of
warn_dollars.
From-SVN: r67824
