* cppfiles.c (stack_include_file): Check for stacked contexts
here.
* cpphash.h (_cpp_do__Pragma): New prototype.
* cppinit.c (cpp_reader_init): Add _Pragma keyword to hash table.
* cpplex.c (skip_escaped_newlines): Only process trigraphs and
escaped newlines if !(buffer->from_stage3).
(_cpp_lex_token): Warn about missing newlines iff
!buffer->from_stage3.
* cpplib.c (get__Pragma_string, destringize,
_cpp_do__Pragma): New functions.
(run_directive): Set output_line for _Pragma to avoid line
markers in output. Set from_stage3 and prevent macro expansion
for _Pragma and command-line options. Check buffer exhaustion.
(cpp_push_buffer): Don't check for stacked macro contexts, as
this is perfectly legitimate for _Pragma. Move the check to
stack_include_file instead. Set from_stage3 iff buffer is
preprocessed input.
* cpplib.h (struct cpp_buffer): Make warned_cplusplus_comments
unsigned. New boolean from_stage3.
(struct spec_nodes): Add n__Pragma.
* cppmacro.c (enter_macro_context): Flip sense of return value.
(_cpp_get_token): Handle _Pragma operator.
From-SVN: r37147
