Re: AC_HEADER_MAJOR vs. glibc 2.25(-to-be)

[Florian Weimer]

On 09/01/2016 04:27 AM, Zack Weinberg wrote:
> glibc 2.25 is going to deprecate the definition of 'major', 'minor',
> and 'makedev' by  sys/types.h; see
> https://sourceware.org/bugzilla/show_bug.cgi?id=19239 for rationale.
> (It was found to be impractical to remove sys/types.h from stdlib.h.)
> Unfortunately, AC_HEADER_MAJOR does not detect that these macros are
> now throwing warning messages if you don't include sys/sysmacros.h,
> and this is reported to break software that uses -Werror (see the very
> end of the above bug report).

The larger question here is whether we can make toolchain changes which 
alter the outcome of checks in existing (compiled) autoconf tests.

More and more, the invalid C used in autoconf tests blocks useful 
enhancements to the toolchain.

Is it reasonable to expect that autoconf releases happen regularly 
(twice a year), to match glibc/GCC/binutils changes, and that people run 
autoconf before compiling software packages?

Florian