The recommended version of FreeBSD to use them is 8-CURRENT.
FreeBSD-7.x is not fully compatible with compat.linux.osrelease
2.6.16. Some syscalls cannot be MFCed due to native FreeBSD
ABI breakage.
Usage (and package building):
1. define compat.linux.osrelease=2.6.16;
2. add following variables to /etc/make.conf:
. OVERRIDE_LINUX_BASE_PORT=f8;
. OVERRIDE_LINUX_NONBASE_PORTS=f8.
Approved by: bsam (me) ;-)