ggml : automatic selection of best CPU backend (#10606)

* ggml : automatic selection of best CPU backend

* amx : minor opt

* add GGML_AVX_VNNI to enable avx-vnni, fix checks

scripts/build-cpu.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+name="$1"
+args="${@:2}"
+
+echo "Building $name with args: $args"
+
+rm -fr build-cpu-$1
+cmake -S . -B build-cpu-$1 -DGGML_BACKEND_DL=ON -DGGML_NATIVE=OFF $args
+cmake --build build-cpu-$1 --config Release -t ggml-cpu -j $(nproc)
+cp build-cpu-$1/bin/libggml-cpu.so ./libggml-cpu-$1.so
+rm -fr build-cpu-$1