Xattrs are not supported

Question

I am trying to perform a little testing of XATTRs. I recompiled my kernel with ALL the XATTRs enabled.

Now, when I include the header of xattrs :

#include <attr/xattr.h>

I receive an error no such file or directory. I am using UBUNTU 11.10 64 bit system, and I cannot understand why XATTRs are not supported ?