Bug#1125354: gcc-11: please disable multilib support on s390x

[Aurelien Jarno <aurel32@debian.org>]

Source: gcc-11
Version: 11.5.0-7
Severity: important
X-Debbugs-Cc: debian-s390@lists.debian.org
User: debian-s390@lists.debian.org
Usertags: s390x 31-bit-removal
Control: affects -1 gcc-11-cross gcc-11-cross-ports

Hi,

Linux 6.19 will drop support for 31-bit compatibility on s390x, and will
also stop providing 31-bit support in UAPI header files [1]. Once this
lands in unstable, it will become impossible to build the libc6-s390 and
libc6-dev-s390 packages on s390x, and in turns the gcc-multilib and
g++-multilib packages.

Therefore please disable multilib support in gcc-11 on s390x. There are
no remaining users. gcc-11-cross and gcc-11-cross-ports will then need a
rebuild.

Please note that this bug will become serious once linux 6.19 reaches
unstable (the upstream release is expected around the beginning of
February).

Regards
Aurelien

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3db5cf9354710c3b9268af74a0dca88514279453