rseq enablement patches overview

[Florian Weimer]

* Florian Weimer:

> Since my patchwork looks rather horrible right now and I posted a bunch
> of vaguely-related cleanups first, here are the patches that currently
> need review for rseq enablement:
>
>   Introduce <elf_machine_sym_no_match.h>
>   <https://sourceware.org/ml/libc-alpha/2019-10/msg00339.html>
>
>     This is needed in the implementation of _dl_lookup_direct in the
>     next patch.
>
>   Implement __libc_early_init
>   <https://sourceware.org/ml/libc-alpha/2019-10/msg00340.html>
>
>     This is the main patch.  rseq should be hooked into
>     __libc_early_init, around the __ctype_init call.
>
>   nptl: Start new threads with all signals blocked [BZ #25098]
>   <https://sourceware.org/ml/libc-alpha/2019-10/msg00383.html>
>
>     This is a long-standing issue which will affect rseq as well.

I reposted these patches:

  <https://sourceware.org/ml/libc-alpha/2019-11/msg00976.html>
  <https://sourceware.org/ml/libc-alpha/2019-11/msg00977.html>
  <https://sourceware.org/ml/libc-alpha/2019-11/msg01016.html>

>   resolv/tst-idna_name_classify: Isolate from system libraries
>   <https://sourceware.org/ml/libc-alpha/2019-10/msg00338.html>
>
>     This is required to fix a test suite failure due to the ld.so static
>     link ABI changing in the __libc_early_init patch.  (I should
>     probably just push this one.)

This patch has been merged.

Thanks,
Florian