sagemathgh-36552: src/sage/misc/cython.py: Fix the workaround for s…

…etuptools_scm

    
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The part of sagemath#36400 that was intended to fix the runtime use of cython
did not actually fix it because `finalize_distribution` is called
already by `Distribution.__init__`.

This shows up when invoked from a directory with `pyproject.toml` or a
similar config file. As the Build & Test workflow invokes the doctester
from `SAGE_ROOT/src`, these errors show up in all tests. Marking it as a
blocker so it is [applied automatically in CI
workflows](https://github.com/sagemath/sage/wiki/Sage-10.2-Release-
Tour#open-blocker-prs-are-applied-automatically-in-ci-workflows)

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Fixes
sagemath#36400 (comment)
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URL: sagemath#36552
Reported by: Matthias Köppe
Reviewer(s): Tobias Diez

src/sage/misc/cython.py

@@ -421,15 +421,20 @@ def cython(filename, verbose=0, compile_message=False,
                         os.curdir)
 
     # This emulates running "setup.py build" with the correct options
-    dist = Distribution()
+    #
     # setuptools plugins considered harmful:
     # If build isolation is not in use and setuptools_scm is installed,
     # then its file_finders entry point is invoked, which we don't need.
     # And with setuptools_scm 8, we get more trouble:
     # LookupError: pyproject.toml does not contain a tool.setuptools_scm section
     # LookupError: setuptools-scm was unable to detect version ...
     # We just remove all handling of "setuptools.finalize_distribution_options" entry points.
-    dist._removed = staticmethod(lambda ep: True)
+    class Distribution_no_finalize_distribution_options(Distribution):
+        @staticmethod
+        def _removed(ep):
+            return True
+
+    dist = Distribution_no_finalize_distribution_options()
     dist.ext_modules = [ext]
     dist.include_dirs = includes
     buildcmd = dist.get_command_obj("build")