What steps will reproduce the problem?
1. Try to compile vim 7.4.238+ on a host with Linux kernel version < 2.6.36 
(e.g. RHEL 6.4, kernel 2.6.32)

What is the expected output? What do you see instead?

The smack configure check, added in patch 238 and enabled by default, checks 
for the 'llistxattr' symbol and the xattr.h header. The symbol and include both 
exist in Linux versions older than 2.6.36, which causes HAVE_SMACK to be set.

However, the smack code in os_unix.c makes use of XATTR_NAME_* defines that 
were introduced 2.6.36 
(http://lxr.free-electrons.com/source/include/linux/xattr.h?v=2.6.36). This 
causes the compile to fail.

What version of the product are you using? On what operating system?

Vim 7.4.238+, RHEL 6.4 Linux kernel version 2.6.32

Please provide any additional information below.

If possible, the configure check code should use the XATTR_NAME_* defines it 
uses in os_unix.c, such that the check fails when compiled against a kernel 
where those defs don't exist.