* Richard W. M. Jones:
> > This is with glibc-2.31.9000-19.fc33.x86_64. I can see
that
> > sys_errlist is a symbol still in /lib64/libc.so.
>
> Yes, but it's a compat symbol, so not available for linking.
>
> What is the test file autoconf feeds to the compiler?
I believe the test file is actually just
extern int sys_errlist; char *p = &sys_errlist;
(see
https://github.com/libguestfs/libnbd/blob/a6ba108309d9250e5f7fe0a5d41a996...)
That can't work because there's no main function, so linking that would
always fail.
I suspect that the fragment lands in the body of main, where the
reference to sys_errlist is simply optimized away.
Thanks,
Florian