add binaries for windows and mac

mk/install-build-tools.ps1

@@ -0,0 +1,6 @@
+# TODO: Lock this down to a specific commit instead of always using the latest.
+git clone `
+    --branch windows `
+    --depth 1 `
+    https://github.com/briansmith/ring-toolchain `
+    target/tools/windows

mk/install-build-tools.sh

@@ -0,0 +1,86 @@
+#!/usr/bin/env bash
+#
+# Copyright 2020 Brian Smith.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+set -eux -o pipefail
+IFS=$'\n\t'
+
+target=$1
+features=${2-}
+
+function install_packages {
+  sudo apt-get -yq --no-install-suggests --no-install-recommends install "$@"
+}
+
+use_clang=
+case $target in
+--target*android*)
+  mkdir -p "${ANDROID_SDK_ROOT}/licenses"
+  android_license_file="${ANDROID_SDK_ROOT}/licenses/android-sdk-license"
+  accept_android_license=24333f8a63b6825ea9c5514f83c2829b004d1fee
+  grep --quiet --no-messages "$accept_android_license" "$android_license_file" \
+    || echo $accept_android_license  >> "$android_license_file"
+  "${ANDROID_SDK_ROOT}/cmdline-tools/latest/bin/sdkmanager" ndk-bundle
+  ;;
+esac
+
+case $target in
+--target=aarch64-unknown-linux-gnu)
+  # Clang is needed for code coverage.
+  use_clang=1
+  install_packages \
+    qemu-user \
+    gcc-aarch64-linux-gnu \
+    libc6-dev-arm64-cross
+  ;;
+--target=aarch64-unknown-linux-musl|--target=armv7-unknown-linux-musleabihf)
+  use_clang=1
+  install_packages \
+    qemu-user
+  ;;
+--target=arm-unknown-linux-gnueabihf)
+  install_packages \
+    qemu-user \
+    gcc-arm-linux-gnueabihf \
+    libc6-dev-armhf-cross
+  ;;
+--target=i686-unknown-linux-gnu)
+  use_clang=1
+  install_packages \
+    gcc-multilib \
+    libc6-dev-i386
+  ;;
+--target=i686-unknown-linux-musl|--target=x86_64-unknown-linux-musl)
+  use_clang=1
+  ;;
+--target=wasm32-unknown-unknown)
+  # The version of wasm-bindgen-cli must match the wasm-bindgen version.
+  wasm_bindgen_version=$(cargo metadata --format-version 1 | jq -r '.packages | map(select( .name == "wasm-bindgen")) | map(.version) | .[0]')
+  cargo install wasm-bindgen-cli --vers "$wasm_bindgen_version" --bin wasm-bindgen-test-runner
+  use_clang=1
+  ;;
+--target=*)
+  ;;
+esac
+
+if [ -n "$use_clang" ]; then
+  # https://github.com/rust-lang/rust/pull/79365 upgraded the coverage file
+  # format to one that only LLVM 11+ can use
+  llvm_version=12
+  sudo apt-key add mk/llvm-snapshot.gpg.key
+  sudo add-apt-repository "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-$llvm_version main"
+  sudo apt-get update
+  install_packages clang-$llvm_version llvm-$llvm_version
+fi