GCC defines built-ins for atomic instructions found on i486 and higher.
Because FreeBSD no longer supports the 80386 cpu all code targeting
FreeBSD/i386 necessarily runs on i486 or higher so the compiler
built-ins can be used by default inside libstdc++ and in C++ headers.
This allows newly compiled C++ code to inline some atomic operations.
Old binaries continue to use libstdc++ functions.

PR:		148926
Tested by:	Yuri Karaban <tech askold net>
Approved by:	kib (mentor)

  Approved by:	cognet (mentor)

Also:
        Switch FreeBSD to use libgcc_s.so.1.

        Use dl_iterate_phdr to locate shared objects' exception frame
        info instead of depending on older register_frame_info machinery.
        This allows us to avoid depending on libgcc_s.so.1 in binaries
        that do not use exception handling directly. As an additional
        benefit it breaks circular libc <=> libgcc_s.so.1 dependency too.

        Build newly added libgomp.so.1 library, the runtime support
        bits for OpenMP.

        Build LGPLed libssp library. Our libc provides our own
        BSD-licensed SSP callbacks implementation, so this library
        is only built to benefit applications that have hadcoded
        knowledge of libssp.so and libssp_nonshared.a. When linked
        in from command line, these libraries override libc
        implementation.

already available.

they are not visible from wchar.h.

Prodded by:	stefanf