XNNPACK neural network inference operators (RVV build)

 XNNPACK is a highly optimized library of floating-point and quantized neural
 network inference operators for ARM, x86, WebAssembly, and RISC-V. This
 package provides the shared library, the production micro-kernel archive and
 the public headers, built for RISC-V with the RVV (vector) extension enabled
 (-march=rv64gcv / rv64gcv_zvfh).