Fix pthreads getrlimit, gettimeofday namespace (bug 17682)

[Ondřej Bílka]

On Fri, Dec 05, 2014 at 05:30:43PM +0000, Joseph Myers wrote:
> Some pthreads functions use getrlimit and gettimeofday, but these
> functions are XSI, not base POSIX; this is a namespace issue for
> dynamic linking as well as static linking.  This patch makes them use
> __getrlimit and __gettimeofday instead - the former needed to be newly
> exported from libc.so at GLIBC_PRIVATE (and so now needs
> libc_hidden_proto / libc_hidden_def), the latter was already exported.
> 
> Tested for x86_64 (testsuite, and that disassembly of installed shared
> libraries is unchanged by the patch).
> 
Looks ok.