Swift 6, SwiftUnicodeDataTables, Other Improvements (#106)

* Require Swift 6 and tools v6

* Fix build error

* Remove pdc flag skip-unown

* Add build flag for linking swiftUnicodeDataTables

* Improve swift toolchain lookup

* Use clang in swift toolchain

* Improve product module lookup

* Add documentation

* Fix build errors

* Chip away at deprecations

* Remove merge conflict junk

* Add hack for SwiftUnicodeDataTables

* Use chosen Playdate SDK

* Show built pdx path in build output

* Improve build output

* Add swiftUnicodeDataTables source as a module

* Export so symbols are available

* Remove linking hacks

* Fix deprecations

* Add support for C/C++ modules

* Fix deprecation

* Link compiled Clang libraries

* Continue Add support for C/C++ modules

* Remove unused var

* Use Task

* Remove explicit cxx language mode

* Remove debug symbols from pdx

* Verify file exists first

* Fix flag order

Flags were being ignored by the pdc cli

* Increase output clarity

* Remove trailing slash

URL takes care of this. The previous Path type did not

* Remove tmp debug output

* Revert fix flag order

* Add output note

Package.swift

@@ -1,16 +1,7 @@
-// swift-tools-version: 5.10
+// swift-tools-version: 6.0
 
 import PackageDescription
 
-let gccIncludePrefix =
-    "/usr/local/playdate/gcc-arm-none-eabi-9-2019-q4-major/lib/gcc/arm-none-eabi/9.2.1"
-
-let playdateSDKPath: String = if let path = Context.environment["PLAYDATE_SDK_PATH"] {
-    path
-} else {
-    "\(Context.environment["HOME"]!)/Developer/PlaydateSDK/"
-}
-
 let package = Package(
     name: "PlaydateKit",
     platforms: [.macOS(.v14)],
@@ -19,32 +10,64 @@ let package = Package(
         .plugin(name: "PDCPlugin", targets: ["PDCPlugin"])
     ],
     targets: [
-        .target(name: "PlaydateKit", dependencies: ["CPlaydate"], swiftSettings: [
-            .enableExperimentalFeature("Embedded"),
-            .unsafeFlags([
-                "-Xfrontend", "-disable-objc-interop",
-                "-Xfrontend", "-disable-stack-protector",
-                "-Xfrontend", "-function-sections",
-                "-Xfrontend", "-gline-tables-only",
-                "-Xcc", "-DTARGET_EXTENSION",
-                "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include",
-                "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include-fixed",
-                "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/../../../../arm-none-eabi/include",
-                "-I", "\(playdateSDKPath)/C_API"
-            ]),
-        ]),
-        .target(name: "CPlaydate", cSettings: [
-            .unsafeFlags([
-                "-DTARGET_EXTENSION",
-                "-I", "\(gccIncludePrefix)/include",
-                "-I", "\(gccIncludePrefix)/include-fixed",
-                "-I", "\(gccIncludePrefix)/../../../../arm-none-eabi/include",
-                "-I", "\(playdateSDKPath)/C_API"
-            ])
-        ]),
+        .target(
+            name: "PlaydateKit", 
+            dependencies: ["CPlaydate", "SwiftUnicodeDataTables"], 
+            swiftSettings: swiftSettings
+        ),
+        .target(
+            name: "CPlaydate",
+            cSettings: [
+                .unsafeFlags([
+                    "-DTARGET_EXTENSION",
+                    "-I", "\(gccIncludePrefix)/include",
+                    "-I", "\(gccIncludePrefix)/include-fixed",
+                    "-I", "\(gccIncludePrefix)/../../../../arm-none-eabi/include",
+                    "-I", "\(playdateSDKPath)/C_API"
+                ])
+            ]
+        ),
+        .target(
+            name: "SwiftUnicodeDataTables",
+            cxxSettings: [
+                .define("SWIFT_STDLIB_ENABLE_UNICODE_DATA")
+            ]
+        ),
         .plugin(
             name: "PDCPlugin",
-            capability: .command(intent: .custom(verb: "pdc", description: "Runs the Playdate compiler"))
-        )
-    ]
+            capability: .command(intent:
+                    .custom(verb: "pdc", description: "Runs the Playdate compiler")
+            )
+        ),
+    ],
+    swiftLanguageModes: [.v6]
 )
+
+
+// MARK: - Helper Variables
+// note: These must be computed variables when beneath the `let package =` declaration.
+
+var swiftSettings: [SwiftSetting] {[
+    .enableExperimentalFeature("Embedded"),
+    .unsafeFlags([
+        "-whole-module-optimization",
+        "-Xfrontend", "-disable-objc-interop",
+        "-Xfrontend", "-disable-stack-protector",
+        "-Xfrontend", "-function-sections",
+        "-Xfrontend", "-gline-tables-only",
+        "-Xcc", "-DTARGET_EXTENSION",
+        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include",
+        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/include-fixed",
+        "-Xcc", "-I", "-Xcc", "\(gccIncludePrefix)/../../../../arm-none-eabi/include",
+        "-I", "\(playdateSDKPath)/C_API"
+    ]),
+]}
+var gccIncludePrefix: String {
+    "/usr/local/playdate/gcc-arm-none-eabi-9-2019-q4-major/lib/gcc/arm-none-eabi/9.2.1"
+}
+var playdateSDKPath: String {
+    if let path = Context.environment["PLAYDATE_SDK_PATH"] {
+        return path
+    }
+    return "\(Context.environment["HOME"]!)/Developer/PlaydateSDK/"
+}