* Makefile.in (cc1): Put C_OBJS, and thence @extra_c_objs@ last.
        (LIBCPP_OBJS): New.  Add cppulp.o.
        (cppmain, fix-header): Depend on and use libcpp.a.
        * configure.in (extra_c_objs, extra_cxx_objs): Use libcpp.a instead
        of the individual object files.
        * objc/Make-lang.in (cc1obj): Put OBJC_OBJS, and thence @extra_c_objs@,
        last.
        * cccp.c (user_label_prefix): New.
        (main): Set it off -f*leading-underscore.
        (special_symbol): Use it.
        * cpplib.c (special_symbol): Likewise.
        (cpp_handle_option): Handle -f*leading-underscore.
        * cppulp.c: New file.
        * output.h (user_label_prefix): Declare it.
        * dwarf2out.c (ASM_NAME_TO_STRING): Prepend user_label_prefix.
        * toplev.c (f_options, main): Handle -f*leading-underscore.
        * defaults.h (ASM_OUTPUT_LABELREF): Use asm_fprintf instead of
        referencing USER_LABEL_PREFIX directly.
        * config/nextstep.h (ASM_OUTPUT_LABELREF): Likewise.
        * m32r/m32r.h (ASM_OUTPUT_LABELREF): Likewise.
        * final.c (asm_fprintf): Use user_label_prefix instead.
        * arm/thumb.c (thumb_print_operand): Likewise.
        * gcc.c (default_compilers): Pass -f*leading-underscore on to
        cpp wherever appropriate.

From-SVN: r23415