Allow LIBDIR override and IPv6 opt out
Created by: ony
For proper installing miniupnpc in Exherbo it will be good to have these changes or similar in upstream code. The reason for this patch is that at 64bit platform where .../lib64 is used we need to have a chance to override default .../lib variant. Also when there is no IPv6 support enabled one of the tests hangs:
miniwget validation test
./testminiwget.sh
socket: Address family not supported by protocol
Thank you