sig{set,long}jmp: do not ignore sigsetjmp's second argument

Origin: https://git.kernel.org/pub/scm/libs/klibc/klibc.git/commit/?id=eb10cf8c3128612a089ace8489a81bc4ffd5d07a
Bug-Debian: https://bugs.debian.org/988027

Save and restore the signal mask only if that argument is nonzero,
as required by the standards.  (Closes: Debian #988027)

Signed-off-by: mirabilos <tg@debian.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Name sig-set-long-jmp-do-not-ignore-sigsetjmp-s-second-ar.patch

klibc (2.0.9-1) unstable; urgency=medium

  * New upstream version
  * armhf: Update compiler options for gcc 11 (Closes: #996906)
  * sig{set,long}jmp: do not ignore sigsetjmp's second argument
    (Closes: #988027)
  * Fix implementation of utimes

[dgit import unpatched klibc 2.0.9-1]

Import klibc_2.0.9.orig.tar.xz

[dgit import orig klibc_2.0.9.orig.tar.xz]

Import klibc_2.0.9-1.debian.tar.xz

[dgit import tarball klibc 2.0.9-1 klibc_2.0.9-1.debian.tar.xz]