In glibc-2.23 <sys/sysmacros.h> isn't automatically included in
<sys/types.h> [1], so we need ot explicitely include it.
https://sourceware.org/ml/libc-alpha/2015-11/msg00253.html
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Justin Lecher <jlec@gentoo.org>
Closes#6132