glibc 2.5 compat: use correct header for makedev() et al.

glibc 2.5 compat: use correct header for makedev() et al.

In glibc 2.5, makedev(), major(), and minor() are defined in
sys/sysmacros.h.  They are also defined in types.h for backward
compatability, but using these definitions triggers a compile warning.
This breaks the ZFS build, as it builds with -Werror.

autoconf email threads indicate these macros may be defined in
sys/mkdev.h in some cases.

This commit adds configure checks to detect where makedev() is defined:
  sys/sysmacros.h
  sys/mkdev.h

It assumes major() and minor() are defined in the same place.

The libspl types.h then includes
	sys/sysmacros.h (preferred) or
	sys/mkdev.h (2nd choice)
if one of those defines makedev().

This is done before including the system types.h.

An alternative would be to remove uses of major, minor, and makedev,
instead comparing the st_dev returned from stat64.  These configure
checks would then be unnecessary.

This change revealed that __NORETURN was being defined unnecessarily in
libspl/include/sys/sysmacros.h.  That definition is removed.

The files in which __NORETURN are used all include types.h, and so all
will get the definition provided by feature_tests.h

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #5945