package/python-ruamel-yaml-clib: new package

Add optional c extension for python-ruamel-yaml which can speed up yaml
loading/parsing.

Extend the ruamel-yaml runtime test to check if the c extension works
correctly.

Signed-off-by: Marcus Hoffmann <buildroot@bubu1.eu>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

support/testing/tests/package/sample_python_ruamel_yaml.py

@@ -25,3 +25,15 @@ parsed = yaml.load(yaml_text)
 
 assert parsed['OneMoreRootKey'] == 9.99
 assert parsed['ListRoot'][1]['another-int'] == 1111
+
+# Tests the C extension based loader
+# ruamel.yaml automatically falls back to the pure python version, so we need
+# to explicitly check if importing the CLoader works here.
+# Import this here, so it's clearer what part of the test is failing.
+from ruamel.yaml import CLoader  # noqa: E402
+assert CLoader is not None
+yaml = YAML(typ='safe')
+parsed_from_c = yaml.load(yaml_text)
+
+assert parsed_from_c['OneMoreRootKey'] == 9.99
+assert parsed_from_c['ListRoot'][1]['another-int'] == 1111