dependencies: Add a System Dependency

as a base class for other system dependencies. This will later be used
to to fix the type_name vs name confusion.

mesonbuild/dependencies/system.py

@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright © 2021 Intel Corporation
+
+from .base import ExternalDependency, DependencyMethods
+import typing as T
+
+if T.TYPE_CHECKING:
+    from ..environment import Environment
+
+__all__ = [
+    'SystemDependency',
+]
+
+
+class SystemDependency(ExternalDependency):
+
+    """Dependency base for System type dependencies."""
+
+    def __init__(self, name: str, env: 'Environment', kwargs: T.Dict[str, T.Any],
+                 language: T.Optional[str] = None) -> None:
+        super().__init__('system', env, kwargs, language=language)
+        self.name = name
+
+    @staticmethod
+    def get_methods() -> T.List[DependencyMethods]:
+        return [DependencyMethods.SYSTEM]
+
+    def log_tried(self) -> str:
+        return 'system'