Conform failures in glibc?

[Florian Weimer]

* Steve Ellcey:

> I just ran the glibc testsuite and am seeing a number of conform failures
> with the following messages in the err file:
>
> /tmp/tmprhwms3a9/test.c:1:10: fatal error: ndbm.h: No such file or directory
>     1 | #include <ndbm.h>
>       |          ^~~~~~~~
> compilation terminated.
> In file included from /tmp/tmpyhffvdkg/test.c:1:
> /home/sellcey/gcc_newbuild/install/lib/gcc/aarch64-linux-gnu/10.0.0/include/varargs.h:4:2: error: #error "GCC no longer implements <varargs.h>."
>     4 | #error "GCC no longer implements <varargs.h>."
>       |  ^~~~~
> /home/sellcey/gcc_newbuild/install/lib/gcc/aarch64-linux-gnu/10.0.0/include/varargs.h:5:2: error: #error "Revise your code to use <stdarg.h>."
>     5 | #error "Revise your code to use <stdarg.h>."
>       |  ^~~~~
>

These should be XFAILed and not really count as failures.

I find these errors confusing as well.  On the one hand, I think want
the conform test expectations to reflect POSIX as closely as possible,
but on the other hand, I do not see value in carrying around such fringe
XFAILs forever.  The <varargs.h> one in particular will never get fixed
at this point.  We know that, so reporting it over and over again is
just noise.

Thanks,
Florian