Use -fbuilding-libgcc for more target macros used in libgcc

[Dominique Dhumieres]

On Thu, Sep 4, 2014 at 6:15 PM, Joseph S. Myers <joseph@codesourcery.com> wrote:
>
> gcc/c-family:
> 2014-09-05  Joseph Myers  <joseph@codesourcery.com>
>
>         * c-cppbuiltin.c (c_cpp_builtins): Also define
>         __LIBGCC_EH_TABLES_CAN_BE_READ_ONLY__,
>         __LIBGCC_EH_FRAME_SECTION_NAME__, __LIBGCC_JCR_SECTION_NAME__,
>         __LIBGCC_CTORS_SECTION_ASM_OP__, __LIBGCC_DTORS_SECTION_ASM_OP__,
>         __LIBGCC_TEXT_SECTION_ASM_OP__, __LIBGCC_INIT_SECTION_ASM_OP__,
>         __LIBGCC_INIT_ARRAY_SECTION_ASM_OP__,
>         __LIBGCC_STACK_GROWS_DOWNWARD__,
>         __LIBGCC_DONT_USE_BUILTIN_SETJMP__,
>         __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__,
>         __LIBGCC_DWARF_FRAME_REGISTERS__,
> ...

This breaks bootstrap on x86_64-apple-darwin13, see

https://gcc.gnu.org/ml/gcc-bugs/2014-09/msg01135.html

TIA

Dominique