Integrate CAtk as a system library

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:4.0
+// swift-tools-version:4.2
 
 import PackageDescription
 
@@ -8,11 +8,15 @@ let package = Package(
         .library(name: "Atk", targets: ["Atk"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/rhx/CAtk.git", .branch("master")),
         .package(url: "https://github.com/rhx/SwiftGObject.git", .branch("master"))
     ],
     targets: [
-        .target(name: "Atk", dependencies: ["GLibObject"]),
+	.systemLibrary(name: "CAtk", pkgConfig: "atk glib-2.0 gio-unix-2.0",
+	    providers: [
+		.brew(["atk", "glib", "glib-networking", "gobject-introspection"]),
+		.apt(["libatk1.0-dev", "libglib2.0-dev", "glib-networking", "gobject-introspection", "libgirepository1.0-dev"])
+	    ]),
+        .target(name: "Atk", dependencies: ["CAtk", "GLibObject"]),
         .testTarget(name: "AtkTests", dependencies: ["Atk"]),
     ]
 )

Sources/CAtk/atk_bridging.h

@@ -0,0 +1,20 @@
+struct _AtkAction {};
+struct _AtkComponent {};
+struct _AtkDocument {};
+struct _AtkEditableText {};
+struct _AtkHyperlinkImpl {};
+struct _AtkHypertext {};
+struct _AtkImage {};
+struct _AtkImplementor {};
+struct _AtkRange {};
+struct _AtkSelection {};
+struct _AtkStreamableContent {};
+struct _AtkTable {};
+struct _AtkTableCell {};
+struct _AtkText {};
+struct _AtkValue {};
+struct _AtkWindow {};
+
+#define GLIB_DISABLE_DEPRECATION_WARNINGS
+#include <sys/types.h>
+#include <atk/atk.h>

Sources/CAtk/module.modulemap

@@ -0,0 +1,8 @@
+module CAtk [system] {
+	header "atk_bridging.h"
+
+	link "gobject-2.0"
+	link "glib-2.0"
+
+	export *
+}