* cppfiles.c (cpp_make_system_header): Take 2 booleans,
        and operate on current buffer.
        (cpp_read_file): Rename _cpp_read_file.
        * cpplib.c (do_line, do_pragma_system_header): Update calls to
        cpp_make_system_header.
        * fix-header.c: Similarly.
        * cpphash.h (_cpp_read_file): Move from...
        * cpplib.h: ... here.
        * cppinit.c (do_includes, cpp_start_read): Update appropriately.

From-SVN: r37989