Add libffi buildscript for Apple Silicon

kotlin-native/tools/libffi/build_for_macos.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+set -eou pipefail
+
+OUTPUT_PATH=${1?"Usage: $0 <output path>"}
+if [ ! -d "$OUTPUT_PATH" ]; then
+  echo "$(realpath "$OUTPUT_PATH") does not exists"
+  exit 1
+fi
+
+if [ -z "$(sysctl -q hw.optional.arm64)" ]
+then
+  ARCH=x86_64
+else
+  ARCH=arm64
+fi
+
+VERSION=1
+NAME=libffi-3.3-$VERSION-macos-$ARCH
+
+pushd "$(mktemp -d -t libffi)"
+curl -LO https://github.com/libffi/libffi/releases/download/v3.3/libffi-3.3.tar.gz
+tar -xf libffi-3.3.tar.gz
+pushd libffi-3.3
+
+# Apple Silicon-specific patch.
+# Based on:
+# * https://github.com/libffi/libffi/pull/565
+# * https://github.com/libffi/libffi/pull/621
+curl -LO https://raw.githubusercontent.com/Homebrew/formula-patches/06252df03c68aee70856e5842f85f20b259e5250/libffi/libffi-3.3-arm64.patch
+patch -p1 --ignore-whitespace < "libffi-3.3-arm64.patch"
+
+./configure --prefix="$(pwd)/$NAME" --disable-docs --enable-shared=no
+make install
+tar -czf "$OUTPUT_PATH"/$NAME.tar.gz "$NAME"
+popd
+popd