Add Linux ARM64 vcpkg support

hatch_cpp/tests/test_vcpkg_ref.py

@@ -83,6 +83,10 @@ def test_explicit_vcpkg_ref_commit_sha(self):
         cfg = HatchCppVcpkgConfiguration(vcpkg_ref=sha)
         assert cfg.vcpkg_ref == sha
 
+    def test_linux_arm64_triplet(self):
+        cfg = HatchCppVcpkgConfiguration(vcpkg_triplet="arm64-linux")
+        assert cfg.vcpkg_triplet == "arm64-linux"
+
 
 class TestResolveVcpkgRef:
     """Tests for _resolve_vcpkg_ref priority logic."""
@@ -163,6 +167,17 @@ def test_generate_uses_posix_command_paths(self, tmp_path, monkeypatch):
         assert "./vcpkg/bootstrap-vcpkg.sh" in commands
         assert "./vcpkg/vcpkg install --triplet x64-linux" in commands
 
+    def test_generate_detects_linux_arm64_triplet(self, tmp_path, monkeypatch):
+        monkeypatch.chdir(tmp_path)
+        monkeypatch.setattr("hatch_cpp.toolchains.vcpkg.sys_platform", "linux")
+        monkeypatch.setattr("hatch_cpp.toolchains.vcpkg.platform_machine", lambda: "aarch64")
+        self._make_vcpkg_env(tmp_path)
+
+        cfg = HatchCppVcpkgConfiguration()
+        commands = cfg.generate(None)
+
+        assert "./vcpkg/vcpkg install --triplet arm64-linux" in commands
+
     def test_generate_uses_windows_command_paths(self, tmp_path, monkeypatch):
         monkeypatch.chdir(tmp_path)
         monkeypatch.setattr("hatch_cpp.toolchains.vcpkg.sys_platform", "win32")

hatch_cpp/toolchains/vcpkg.py

@@ -24,14 +24,15 @@
     "x86-windows",
     "arm-neon-android",
     "arm64-android",
+    "arm64-linux",
     "arm64-osx",
     "arm64-uwp",
     "arm64-windows",
     "arm64-windows-static-md",
 ]
 VcpkgPlatformDefaults = {
     ("linux", "x86_64"): "x64-linux",
-    # ("linux", "arm64"): "",
+    ("linux", "aarch64"): "arm64-linux",
     ("darwin", "x86_64"): "x64-osx",
     ("darwin", "arm64"): "arm64-osx",
     ("win32", "x86_64"): "x64-windows-static-md",