+ USE_SELINUX
+ if set to 'true', SELinux support for udev will be built in.
+ This requires that SELinux development headers and libraries be
+ present on your system to build properly. Default value is
+ 'false'.
+ DEBUG
+ if set to 'true', debugging messages will be sent to the syslog
+ as udev is run. Default value is 'false'.
+ KERNEL_DIR
+ If this is not set it will default to /lib/modules/`uname -r`/build
+ This is used if USE_KLIBC=true to find the kernel include
+ directory that klibc needs to build against. This must be set
+ if you are not building udev while running a 2.6 kernel.