BUG: adjust to older pyproject-metadata releases

Author: dnicolodi

mesonpy/__init__.py

@@ -78,6 +78,7 @@ def canonicalize_license_expression(s: str) -> str:
 
 __version__ = '0.17.0.dev0'
 
+_PYPROJECT_METADATA_VERSION = tuple(map(int, pyproject_metadata.__version__.split('.')[:2]))
 
 _NINJA_REQUIRED_VERSION = '1.8.2'
 _MESON_REQUIRED_VERSION = '0.63.3' # keep in sync with the version requirement in pyproject.toml
@@ -244,6 +245,9 @@ class MesonBuilderError(Error):
 
 class Metadata(pyproject_metadata.StandardMetadata):
     def __init__(self, name: str, *args: Any, **kwargs: Any):
+        if _PYPROJECT_METADATA_VERSION < (0, 9):
+            kwargs.pop('license', None)
+            kwargs.pop('license_files', None)
         super().__init__(name, *args, **kwargs)
         # Local fix for https://github.com/FFY00/python-pyproject-metadata/issues/60
         self.name = self._validate_name(name)