Modern distributions place xattr.h in /usr/include/sys, and fold
libattr.so into libc. They also don't have an ENOATTR.
Make configure detect this, and add a qemu-xattr.h file that
directs the #include to the right place.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
