On <asm/termbits.h> and <asm/termios.h> usage in man pages

Hi!

I was just refreshing my mind about documentation around TIOCGWINSZ,
and noticed the weird <asm/termbits.h> and <asm/termios.h> usage in
various ioctl man pages.

These originate from commit c023614536251bd6b47a0eab45ab3bcfd2ad9ec2,
where it states that the «struct termios» definitions in the
<termios.h> header are incompatible with the defined ioctl calls.

This seems problematic, for one because the <asm/*> headers are Linux
specific, so they reduce portability for all these macros, even when
they do not rely or make use of «struct termios». For another because if
there is a problem in glibc with the interaction between «struct termios»
and the ioctl calls, then that should be fixed in glibc, instead of
adding these workarounds in the man pages.

It seems the problem is that in glibc «struct termios» maps to the Linux
«struct termios2», but the macros for ioctls that use «struct termios»
do not match (for example TCGETS instead of TCGETS2)?


I think this should be fixed both in glibc, to make the definitions
coherent, and in man-pages to not use those Linux-only headers where
it is not necessary and then on a second stage to point back to the
portable headers once glibc has been fixed?

Thanks,
Guillem