[glibc] nptl: Add missing placeholder abi symbol from nanosleep move

[Florian Weimer]

* Adhemerval Zanella:

> https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4f4bb489e0ddd2f24b2a5d352bb39f8dcdb38050
>
> commit 4f4bb489e0ddd2f24b2a5d352bb39f8dcdb38050
> Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
> Date:   Thu Nov 7 15:10:35 2019 +0000
>
>     nptl: Add missing placeholder abi symbol from nanosleep move
>     
>     Adds the __libpthread_version_placeholder symbol with the same version
>     of nanosleep/__nanosleep that was removed by 79a547b162657b3f and that
>     is not provided by other symbols.

> +GLIBC_2.2 __libpthread_version_placeholder F

Sorry, this fix does not look correct to me.  Since GLIBC_2.2 has
members (and we can easily detect that), it should not get an additional
placeholder symbol.

I think you need to add a symbol alias and another compat_symbol to
nptl/libpthread-compat.c.

Thanks,
Florian