Add install cmake action

.github/actions/install-cmake/action.yml

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+name: 'Install CMake'
+description: 'Download and install CMake'
+
+inputs:
+  cmake-version:
+    description: "CMake version (e.g. '3.30.2')"
+    required: true
+  hash:
+    description: "Expected SHA-256 hash of the target archive (Required)."
+    required: true
+  install_dir:
+    description: "Location where to install CMake"
+    required: false
+    default: ""
+
+outputs:
+  cmake-dir:
+    description: "Directory containing the CMake binaries"
+    value: ${{ steps.install.outputs.cmake-dir }}
+  cmake:
+    description: "Path to the installed CMake binary"
+    value: ${{ steps.install.outputs.cmake-path }}
+  ctest:
+    description: "Path to the installed CTest binary"
+    value: ${{ steps.install.outputs.ctest-path }}
+
+runs:
+  using: "composite"
+  steps:
+    - name: Run CMake Installer
+      id: install
+      shell: bash
+      env:
+        CMAKE_VERSION: ${{ inputs.cmake-version }}
+        CMAKE_SHA256: ${{ inputs.hash }}
+        CMAKE_INSTALL_DIR: ${{ inputs.install_dir }}
+        RAW_ACTION_PATH: ${{ github.action_path }}
+      run: |
+        # Resolve path whether running on the host runner or inside a Docker container
+        SCRIPT_PATH="${RAW_ACTION_PATH}/install-cmake.sh"
+        if [ ! -f "${SCRIPT_PATH}" ]; then
+          CONTAINER_PATH="$(echo "${RAW_ACTION_PATH}" | sed 's|^/home/runner/work|/__w|')"
+          if [ -f "${CONTAINER_PATH}/install-cmake.sh" ]; then
+            SCRIPT_PATH="${CONTAINER_PATH}/install-cmake.sh"
+          elif [ -f "${GITHUB_WORKSPACE}/.github/actions/install-cmake/install-cmake.sh" ]; then
+            SCRIPT_PATH="${GITHUB_WORKSPACE}/.github/actions/install-cmake/install-cmake.sh"
+          fi
+        fi
+
+        bash "${SCRIPT_PATH}"

.github/actions/install-cmake/install-cmake.sh

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+#!/bin/bash
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the Swift.org open source project
+##
+## Copyright (c) YEARS Apple Inc. and the Swift project authors
+## Licensed under Apache License v2.0 with Runtime Library Exception
+##
+## See https://swift.org/LICENSE.txt for license information
+## See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+##
+##===----------------------------------------------------------------------===##
+set -euo pipefail
+
+VERSION="${CMAKE_VERSION:?CMAKE_VERSION is required}"
+EXPECTED_SHA="${CMAKE_SHA256:?CMAKE_SHA256 is required}"
+OS="${RUNNER_OS:?RUNNER_OS is required}"
+ARCH="${RUNNER_ARCH:?RUNNER_ARCH is required}"
+TEMP_DIR="${RUNNER_TEMP:?RUNNER_TEMP is required}"
+
+# Normalize hash to lowercase and strip whitespace
+EXPECTED_SHA=$(echo "${EXPECTED_SHA}" | tr '[:upper:]' '[:lower:]' | xargs)
+
+# 1. Determine destination directory (fallback to $RUNNER_TEMP/cmake-<version> if unset/empty)
+DEST_DIR="${CMAKE_INSTALL_DIR:-}"
+if [ -z "${DEST_DIR}" ]; then
+  DEST_DIR="${TEMP_DIR}/cmake-${VERSION}"
+fi
+
+# 2. Determine archive filename, binary subpath, and binary extension
+BIN_EXT=""
+case "${OS}" in
+  Linux)
+    case "${ARCH}" in
+      X64)   ARCH_NAME="x86_64" ;;
+      ARM64) ARCH_NAME="aarch64" ;;
+      *) echo "::error::Unsupported Linux architecture: ${ARCH}"; exit 1 ;;
+    esac
+    ARCHIVE="cmake-${VERSION}-linux-${ARCH_NAME}.tar.gz"
+    BIN_SUBPATH="bin"
+    ;;
+  macOS)
+    ARCHIVE="cmake-${VERSION}-macos-universal.tar.gz"
+    BIN_SUBPATH="CMake.app/Contents/bin"
+    ;;
+  Windows)
+    case "${ARCH}" in
+      X64)   ARCH_NAME="x86_64" ;;
+      ARM64) ARCH_NAME="arm64" ;;
+      *) echo "::error::Unsupported Windows architecture: ${ARCH}"; exit 1 ;;
+    esac
+    ARCHIVE="cmake-${VERSION}-windows-${ARCH_NAME}.zip"
+    BIN_SUBPATH="bin"
+    BIN_EXT=".exe"
+    ;;
+  *)
+    echo "::error::Unsupported OS: ${OS}"
+    exit 1
+    ;;
+esac
+
+ARCHIVE_URL="https://github.com/Kitware/CMake/releases/download/v${VERSION}/${ARCHIVE}"
+ARCHIVE_PATH="${TEMP_DIR}/${ARCHIVE}"
+
+# 3. Download
+echo "==> Downloading ${ARCHIVE_URL}..."
+curl -fsSL --retry 3 -o "${ARCHIVE_PATH}" "${ARCHIVE_URL}"
+
+# 4. Verify SHA-256 directly in one step
+echo "==> Verifying SHA-256..."
+CHECK_CMD=$(command -v sha256sum || echo "shasum -a 256")
+echo "${EXPECTED_SHA}  ${ARCHIVE_PATH}" | ${CHECK_CMD} -c -
+
+# 5. Extract into destination directory
+echo "==> Extracting into ${DEST_DIR}..."
+mkdir -p "${DEST_DIR}"
+
+if [[ "${ARCHIVE}" == *.tar.gz ]]; then
+  tar -xzf "${ARCHIVE_PATH}" -C "${DEST_DIR}" --strip-components=1
+elif [[ "${ARCHIVE}" == *.zip ]]; then
+  UNZIP_TEMP="${TEMP_DIR}/unzip_tmp"
+  mkdir -p "${UNZIP_TEMP}"
+  unzip -q -o "${ARCHIVE_PATH}" -d "${UNZIP_TEMP}"
+  TOP_DIR=$(find "${UNZIP_TEMP}" -mindepth 1 -maxdepth 1 -type d)
+  mv "${TOP_DIR}"/* "${DEST_DIR}/"
+  rm -rf "${UNZIP_TEMP}"
+fi
+rm -f "${ARCHIVE_PATH}"
+
+# 6. Set PATH and GITHUB_OUTPUT
+CMAKE_BIN_DIR="${DEST_DIR}/${BIN_SUBPATH}"
+echo "${CMAKE_BIN_DIR}" >> "${GITHUB_PATH}"
+
+if [ -n "${GITHUB_OUTPUT:-}" ]; then
+  {
+    echo "cmake-dir=${CMAKE_BIN_DIR}"
+    echo "cmake-path=${CMAKE_BIN_DIR}/cmake${BIN_EXT}"
+    echo "ctest-path=${CMAKE_BIN_DIR}/ctest${BIN_EXT}"
+  } >> "${GITHUB_OUTPUT}"
+fi
+
+echo "==> CMake ${VERSION} successfully installed at ${CMAKE_BIN_DIR}"

.github/actions/install-cmake/readme.md

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+# Install CMake
+
+Install an arbitrary version of CMake.
+
+Inputs:
+ - cmake-version: Version of CMake to install (e.g. 3.30.2)
+ - hash: sha256 of the downloaded artifact (.zip or .tar.gz)
+ - intall_dir: (optional) location where to install CMake
+
+Outputs:
+ - cmake-dir: Directory containing the CMake binaries
+ - cmake: Path to the installed CMake binary
+ - ctest: Path to the installed CTest binary
+
+
+## Usage
+
+```yaml
+...
+
+steps:
+
+  ...
+
+  - name: Install CMake
+    id: install-cmake
+    uses: swiftlang/github-workflows/.github/actions/install-cmake@<version>
+    with:
+      cmake-version: 4.0.3
+      hash: 585ae9e013107bc8e7c7c9ce872cbdcbdff569e675b07ef57aacfb88c886faac
+
+  - name: Run Build
+    shell: bash
+    env:
+      CMAKE: ${{ steps.install-cmake.outputs.cmake }}
+    run: |
+      "$CMAKE" -G Ninja -B build -S <sources> -DCMAKE_BUILD_TYPE=Release
+
+  - name: Run Tests
+    shell: bash
+    env:
+      CTEST: ${{ steps.install-cmake.outputs.ctest }}
+    run: |
+      "$CTEST" --output-on-failure --test-timeout 150 --test-dir build -j
+
+  ...
+```