add a toggle for arm/arm64

Package.swift

@@ -2,6 +2,20 @@
 
 import PackageDescription
 
+#if arch(arm) || arch(arm64)
+let exclude: [String] = []
+let additionalSources: [String] = ["ggml-metal.m"]
+let additionalSettings: [CSetting] = [
+    .unsafeFlags(["-fno-objc-arc"]),
+    .define("GGML_SWIFT"),
+    .define("GGML_USE_METAL")
+]
+#else
+let exclude: [String] = ["ggml-metal.metal"]
+let additionalSources: [String] = []
+let additionalSettings: [CSetting] = []
+#endif
+
 let package = Package(
     name: "llama",
     platforms: [.macOS(.v11)],
@@ -12,26 +26,23 @@ let package = Package(
         .target(
             name: "llama",
             path: ".",
+            exclude: exclude,
             sources: [
                 "ggml.c",
                 "llama.cpp",
                 "ggml-alloc.c",
                 "k_quants.c",
-                "ggml-metal.m",
-            ],
+            ] + additionalSources,
             publicHeadersPath: "spm-headers",
             cSettings: [
                 .unsafeFlags(["-Wno-shorten-64-to-32"]),
-                .unsafeFlags(["-fno-objc-arc"]),
-                .define("GGML_SWIFT"),
-                .define("GGML_USE_METAL"),
                 .define("GGML_USE_K_QUANTS"),
                 .define("GGML_USE_ACCELERATE")
-            ],
+            ] + additionalSettings,
             linkerSettings: [
                 .linkedFramework("Accelerate")
             ]
-        ),
+        )
     ],
     cxxLanguageStandard: .cxx11
 )