Calculate complements by using awk's xor() function with a mask of 0xffffffff
instead of relying on the compl() function which appears to produce broken
results on certain 64bit architectures.
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@34875 3c298f89-4303-0410-b956-a3cf2f4a3e73