Remove the str(n)dup inlines from string/bits/string2.h. Although inlining

 Remove the str(n)dup inlines from string/bits/string2.h.  Although inlining
calls with constant strings shows a small (~10%) performance gain, strdup is
typically used in error reporting code, so not performance critical.
Remove the now unused __need_malloc_and_calloc related defines from stdlib.h.

Rename existing uses of str(n)dup to __str(n)dup so it no longer needs to be
redirected to a builtin.  Also building GLIBC with -Os now no longer shows
localplt or linkname space failures (partial fix for BZ #15105 and BZ #19463).

        [BZ #15105]
        [BZ #19463]
        * elf/dl-cache.c (_dl_load_cache_lookup): Use __strdup.
        * inet/rcmd.c (rcmd_af): Likewise.
        * inet/rexec.c   (rexec_af): Likewise.
        * intl/dcigettext.c (_LIBC): Likewise.
        * intl/finddomain.c (_nl_find_domain): Use strdup expansion.
        * locale/loadarchive.c (_nl_load_locale_from_archive): Use __strdup.
        * locale/setlocale.c (setlocale): Likewise.
        * posix/spawn_faction_addopen.c
        (posix_spawn_file_actions_addopen): Likewise.
        * stdlib/putenv.c (putenv): Use __strndup.
        * sunrpc/svc_simple.c (__registerrpc): Use __strdup.
        * sysdeps/posix/getaddrinfo.c (gaih_inet): Use __strdup/__strndup.
        * include/stdlib.h (__need_malloc_and_calloc): Remove uses.
        (__Need_M_And_C) Remove define/undef.
        * stdlib/stdlib.h (__need_malloc_and_calloc): Remove uses.
        (__malloc_and_calloc_defined): Remove define.
        * string/bits/string2.h (__strdup): Remove define.
        (strdup): Likewise.
        (__strndup): Likewise.
        (strndup): Likewise.