Attempt to resolve windows ci issues

.gitignore

@@ -6,3 +6,4 @@ DerivedData/
 .swiftpm/configuration/registries.json
 .swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
 .netrc
+Package.resolved

Package.swift

@@ -4,6 +4,43 @@
 import PackageDescription
 import CompilerPluginSupport
 
+#if os(Windows)
+let GUISwiftSettings: [SwiftSetting] = [
+  // Instruct the compiler to generate the entry point as `wWinMain`
+  // rather than `main` to ensure that the application is correctly
+  // marked as a GUI application (Windows subsystem).  This is done
+  // by the linker based upon the main entry point.  Simply marking
+  // the subsystem is insufficient as the compiler will materialize
+  // the entry point as `main`, resulting in an undefined symbol.
+  .unsafeFlags([
+    "-Xfrontend", "-entry-point-function-name",
+    "-Xfrontend", "wWinMain",
+  ]),
+]
+let GUILinkerSettings: [LinkerSetting] = [
+]
+#endif
+
+#if os(Windows)
+let macroTarget: Target = Target.macro(
+    name: "MockedMacros",
+    dependencies: [
+        .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
+        .product(name: "SwiftCompilerPlugin", package: "swift-syntax")
+    ],
+    swiftSettings: GUISwiftSettings,
+    linkerSettings: GUILinkerSettings
+)
+#else
+let macroTarget: Target = Target.macro(
+    name: "MockedMacros",
+    dependencies: [
+        .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
+        .product(name: "SwiftCompilerPlugin", package: "swift-syntax")
+    ]
+)
+#endif
+
 let package = Package(
     name: "Mocked",
     platforms: [.macOS(.v10_15), .iOS(.v13), .tvOS(.v13), .watchOS(.v6), .macCatalyst(.v13)],
@@ -25,13 +62,7 @@ let package = Package(
         // Targets are the basic building blocks of a package, defining a module or a test suite.
         // Targets can depend on other targets in this package and products from dependencies.
         // Macro implementation that performs the source transformation of a macro.
-        .macro(
-            name: "MockedMacros",
-            dependencies: [
-                .product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
-                .product(name: "SwiftCompilerPlugin", package: "swift-syntax")
-            ]
-        ),
+        macroTarget,
 
         // Library that exposes a macro as part of its API, which is used in client programs.
         .target(name: "Mocked", dependencies: ["MockedMacros"]),