Problem with configure on Linux in dar-2.6.7.RC3

Hi folks (Denis),

In running ./configure on Linux (Ubuntu 16.04.6 LTS) I find
that the resulting dar has "Extended Attributes support  : NO"
when the system does indeed have Extended Attributes
available.  It appears that this is due to the configure test program
compile failing with:
conftest.cpp: In function 'int main()':
conftest.cpp:139:46: error: 'lgetxattr' was not declared in this scope
  lgetxattr((char *)0, (char *)0, (void *)0, 0);

I find that if I force this test program to include the file
#include <sys/xattr.h>
the compiler error no longer occurs.  It appears that the test
program expects to find xattr defines in #include <attr/xattr.h>,
rather than in sys.

I don't know whether this problem is confined to Ubuntu, or
the 16.04 release, or just generically is not working on Linux.

Regards,
Jon Bayh