Koji build failure with coreutils-7.5

[Jim Meyering]

Roland McGrath wrote:
> I agree with Jeff here.  Sorry, Jim.  I know life is too complicated to

Heh, no need to feel sorry, Roland, unless its for the code pollution.
It's fixed properly, now.  And it's not even that ugly.

> keep track of, but that's just how it is.  A robustly-written application
> really needs to distinguish the build-time vs runtime dependencies it has.
...
> The bottom line is that a properly portable program has to check for ENOSYS
> at runtime now if the function in question has ever existed in a libc
> capable of running on a kernel that does not support that system call.

You should know well that we have to strike a balance here.
There is a limit.  Work-arounds like this are worthwhile only
when the older kernels are in frequent-enough use that not applying
the work-around would cause significant risk or discomfort.

For example, if I were to make coreutils programs run flawlessly on 2.4.*
or earlier kernels even when configured/built against modern headers and
libraries, I suspect there would be significant performance degradation
in a few key tools.  If the degradation didn't impact maintainability,
and were negligible when running on modern systems, then it might be ok.

Unless someone can point out a flaw that causes real trouble,
I'll continue making pragmatic compromises.