Add a smoke test that ensures CMake can find the right linker

Add a simple smoke test to verify that the linker selection works as intended with CMake.

.github/smoke-test/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.25)
+project(gha_setup_swift LANGUAGES Swift)
+add_library(Library Library.swift)

.github/smoke-test/Library.swift

@@ -0,0 +1,3 @@
+import Foundation
+
+public func fortyTwo() -> Int { 42 }

.github/workflows/test-install.yml

@@ -24,5 +24,12 @@ jobs:
         branch: development
         tag: DEVELOPMENT-SNAPSHOT-2023-05-20-a
 
-    - name: check swift version
+    - name: Check Swift version
       run: swift --version
+
+    - name: get macOS smoke test prerequisites
+      if: ${{ runner.os == 'macOS' }}
+      run: brew install ninja
+
+    - name: Smoke test
+      run: cmake -GNinja -S .github/smoke-test -B .cmake-build && cmake --build .cmake-build

.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc