WVCryptoPlugin::decrypt stores a pointer in a uint32, so it cannot
be built for 64-bit until the api is changed. Force it to only
build for 32-bit for now.
Also set -Wno-unused-parameter to silence unnecessary warnings
so I can see the build error.
Change-Id: I7cc13cc1d8a06b17468fab6f3b28886f9af02e24