Bug#1067243: openssh: please build without -fzero-call-used-regs=used on m68k

[Colin Watson <cjwatson@debian.org>]

On Wed, Mar 20, 2024 at 07:14:42PM +0000, Thorsten Glaser wrote:
> I can confirm that appending…
> 
> int snprintf_eta;
> double snprintf_time_per_line;
> int snprintf(char *str, size_t size, const char *format, ...) {
>   snprintf_eta = snprintf_time_per_line;
> }
> 
> … (lightly changed from the above) to the program from
> m4/openssh.m4 OSSH_COMPILER_FLAG_TEST_PROGRAM fails with:
> 
> (pbuild-15711)root@ara2:/tmp# gcc -O2 -fPIE -fno-strict-aliasing -fzero-call-used-regs=used t.c
> during RTL pass: zero_call_used_regs
> t.c: In function 'snprintf':
> t.c:51:1: internal compiler error: in change_address_1, at emit-rtl.cc:2287
>    51 | }
>       | ^
> […]

I don't love overriding snprintf here, since it seems possible that that
could disturb the check on other architectures.  Could you try the
somewhat further reduced patch in
https://salsa.debian.org/ssh-team/openssh/-/tree/zero-call-used-regs-m68k,
please?  I wanted to use the mitchy.debian.net porterbox but I got
ECONNREFUSED.

> Alternatively, just hardcode disabling this flag on m68k for now,
> which we’ll eventually have to revert once GCC is on a fixed release
> (14 probably).

This configure check doesn't use the usual autoconf result caching
arrangements, which makes it a bit more awkward to override from
debian/rules.  There are options, but an extended configure check that I
could send upstream would probably be best.

Thanks,

-- 
Colin Watson (he/him)                              [cjwatson@debian.org]