tools: add more endian.h macros

Add some more macros to tools/endian.h to allow mpssd to be compiled
against glibc < 2.9.

Signed-off-by: Peter Foley <pefoley2@pefoley.com>
Cc: rdunlap@infradead.org
Cc: linux-doc@vger.kernel.org
Cc: sudeep.dutt@intel.com
Cc: nikhil.rao@intel.com
Cc: ashutosh.dixit@intel.com
Cc: akpm@linux-foundation.org
Cc: gregkh@linuxfoundation.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>