Add a shell script to replace the PrepareMetalHeaders plugin

Package.swift

@@ -22,24 +22,12 @@ let package = Package(
         .library(name: "MLXFFT", targets: ["MLXFFT"]),
         .library(name: "MLXLinalg", targets: ["MLXLinalg"]),
         .library(name: "MLXFast", targets: ["MLXFast"]),
-
-        // build support & back end
-        .plugin(
-            name: "PrepareMetalShaders",
-            targets: ["PrepareMetalShaders"]
-        ),
     ],
     dependencies: [
         // for Complex type
         .package(url: "https://github.com/apple/swift-numerics", from: "1.0.0")
     ],
     targets: [
-        // plugin to help build the metal shaders
-        .plugin(
-            name: "PrepareMetalShaders",
-            capability: .buildTool(),
-            path: "Plugins/PrepareMetalShaders"
-        ),
         .target(
             name: "Cmlx",
             exclude: [
@@ -133,10 +121,7 @@ let package = Package(
                 .linkedFramework("Foundation"),
                 .linkedFramework("Metal"),
                 .linkedFramework("Accelerate"),
-            ],
-
-            // run the plugin to build the metal shaders
-            plugins: [.plugin(name: "PrepareMetalShaders")]
+            ]
         ),
         .testTarget(
             name: "CmlxTests",

Source/Cmlx/mlx-generated/metal/arange.h

@@ -0,0 +1,9 @@
+// Copyright © 2023-2024 Apple Inc.
+template <typename T>
+[[kernel]] void arange(
+    constant const T& start,
+    constant const T& step,
+    device T* out,
+    uint index [[thread_position_in_grid]]) {
+  out[index] = start + index * step;
+}