Bug#856337: systemd: please support kernel 4.4, or don't hardcode dm interface versions

[Christian Hofstaedtler]

* Marc Lehmann <debian-reportbug at plan9.de> [170228 02:21]:
> Alternatively, since lvm and dmsetup from stretch do not have any issues
> with kernel 4.4, I suspect systemd hardcodes version numbers in direct
> calls instead of going through e.g. libdevmapper - going through a library
> such as libdevmapper that hanmdles the kernel versions bettrer would also
> take care of this issue, at least for current stretch.

This is a direct result of the dm-ioctl.h header file shipped by the
Linux kernel (and the linux-libc-dev package) - any program compiled
against that official header file will embed the version number used
to build. Building systemd (or anything else) against a newer kernel
will result in this problem for older kernels.

libdevmapper works around this by embedding an old copy of
dm-ioctl.h ...

-c