Add -Wextra (with -Wno-unused-parameter) to unix builds in addition to
-Wall -Werror.
This can successfully build everything in Sai without warnings / errors.
PARENT_SCOPE needs adjusting in a few places for wolfssl to work, and
we need a second level export of USE_WOLFSSL through lib/CMakeLists.txt
Add noi/f32 Sai build for WOLFSSL + MINIMAL_EXAMPLES