The verison of Python-LDAP we now use requires a more strict checking of the
installed version of OpenLDAP. It's not enough to just check for the presence
of ldap.h as we had been doing (LDAP_CONTROL_RELAX). This change expands the
check_header function to also allow specifying a second and third argument,
which are a version number and a #define that's expected to yield a version
number from within a C preprocessor that has included the specified header.
These values are compared by py.sh:cmp_version, which returns yea or nay.


git-svn-id: https://svn.calendarserver.org/repository/calendarserver@12013 e27351fd-9f3e-4f54-a53b-843176b1656c
Back up to xattr 0.6.4, because the release after that requires cffi, which is
super complicated sometimes (like on oel5)


git-svn-id: https://svn.calendarserver.org/repository/calendarserver@12014 e27351fd-9f3e-4f54-a53b-843176b1656c