swift-corelibs-libdispatch: init at swift-5.5-RELEASE

Only currently packaged for Linux, which should be OK because the only
user in Nixpkgs is Deadbeef (which is packaged only for Linux).

pkgs/development/libraries/swift-corelibs-libdispatch/default.nix

···
+{ lib
+, clangStdenv
+, fetchFromGitHub
+, cmake
+, ninja
+, libbsd
+, libsystemtap
+}:
+
+let
+  version = "5.5";
+in clangStdenv.mkDerivation {
+  pname = "swift-corelibs-libdispatch";
+  inherit version;
+
+  outputs = [ "out" "dev" "man" ];
+
+  src = fetchFromGitHub {
+    owner = "apple";
+    repo = "swift-corelibs-libdispatch";
+    rev = "swift-${version}-RELEASE";
+    sha256 = "sha256-MbLgmS6qRSRT+2dGqbYTNb5MTM4Wz/grDXFk1kup+jk=";
+  };
+
+  nativeBuildInputs = [
+    cmake
+    ninja
+  ];
+
+  buildInputs = [
+    libbsd
+    libsystemtap
+  ];
+
+  meta = {
+    description = "Grand Central Dispatch";
+    homepage = "https://github.com/apple/swift-corelibs-libdispatch";
+    platforms = lib.platforms.linux;
+    license = lib.licenses.asl20;
+    maintainers = [ lib.maintainers.cmm ];
+  };
+}

pkgs/top-level/all-packages.nix

···
   honeyvent = callPackage ../servers/tracing/honeycomb/honeyvent { };
 
   mictray = callPackage ../tools/audio/mictray { };
+
+  swift-corelibs-libdispatch = callPackage ../development/libraries/swift-corelibs-libdispatch { };
 }