miniupnpc: Hack around build failure on NetBSD

sed 's/\(.*MINIUPNPC_API_VERSION\s\+\)[0-9]\+/\117/' < miniupnpc.h.bak > miniupnpc.h
sed: 1: "s/\(.*MINIUPNPC_API_VER ...": RE error: trailing backslash (\)

I held back on updating this package because of exactly this error...

(nia)