Add ability to build SDK for macOS hosts

The Microkit tool can now be built for x64 macOS as well as ARM64
macOS, allowing the use of the Microkit SDK in macOS environments.

Note that unlike the Linux Microkit tool, the macOS one will be
dynamically linked due to macOS not supporting statically linked
binaries.

Signed-off-by: Ivan Velickovic <[email protected]>

build_sdk.py

@@ -19,6 +19,7 @@
 from dataclasses import dataclass
 from sys import executable
 from tarfile import open as tar_open, TarInfo
+import platform as host_platform
 
 from typing import Dict, Union, List, Tuple
 
@@ -162,12 +163,27 @@ def build_tool(tool_target: Path) -> None:
     pyoxidizer = ENV_BIN_DIR / "pyoxidizer"
     if not pyoxidizer.exists():
         raise Exception("pyoxidizer does not appear to be installed in your Python environment")
+
+    host_system = host_platform.system()
+    if host_system == "Linux":
+        target_triple = "x86_64-unknown-linux-musl"
+    elif host_system == "Darwin":
+        host_arch = host_platform.machine()
+        if host_arch == "x86_64":
+            target_triple = "x86_64-apple-darwin"
+        elif host_arch == "arm64":
+            target_triple = "aarch64-apple-darwin"
+        else:
+            raise Exception(f"Unexpected Darwin architecture: {host_arch}")
+    else:
+        raise Exception(f"The platform \"{host_system}\" is not supported")
+
     r = system(
-        f"{pyoxidizer} build --release --path tool --target-triple x86_64-unknown-linux-musl"
+        f"{pyoxidizer} build --release --path tool --target-triple {target_triple}"
     )
     assert r == 0
 
-    tool_output = "./tool/build/x86_64-unknown-linux-musl/release/install/microkit"
+    tool_output = f"./tool/build/{target_triple}/release/install/microkit"
 
     r = system(f"strip {tool_output}")
     assert r == 0