`matplotlib` fails to install under Windows on GraalPy 25.0.0

[s5bug]

> pip install matplotlib
C:\Users\Aly\.pyenv\pyenv-win\versions\graalpy-25.0.0-windows-amd64\Lib\ssl.py:527: UserWarning: unable to enumerate Windows certificate store
  warnings.warn("unable to enumerate Windows certificate store")
WARNING: Disabling truststore because platform isn't supported
Looking in indexes: https://pypi.org/simple, https://www.graalvm.org/python/wheels/
Collecting matplotlib
  Downloading matplotlib-3.10.6.tar.gz (34.8 MB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 34.8/34.8 MB 13.3 MB/s eta 0:00:00
  Looking for GraalPy patches for matplotlib
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Installing backend dependencies ... done
  Preparing metadata (pyproject.toml) ... error
  error: subprocess-exited-with-error

  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 2
  ╰─> [17 lines of output]
      + meson setup C:\Users\Aly\AppData\Local\Temp\pip-install-7p4n0793\matplotlib_37da3d368e7447a48e643f1eb3f1aa70 C:\Users\Aly\AppData\Local\Temp\pip-install-7p4n0793\matplotlib_37da3d368e7447a48e643f1eb3f1aa70\.mesonpy-bn__bqvo -Dbuildtype=release -Db_ndebug=if-release -Db_vscrt=md --native-file=C:\Users\Aly\AppData\Local\Temp\pip-install-7p4n0793\matplotlib_37da3d368e7447a48e643f1eb3f1aa70\.mesonpy-bn__bqvo\meson-python-native-file.ini
      Traceback (most recent call last):
        File "C:\Users\Aly\AppData\Local\Temp\pip-build-env-069mgoq7\overlay\Lib\site-packages\mesonbuild\mesonmain.py", line 193, in run
          return options.run_func(options)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^
        File "C:\Users\Aly\AppData\Local\Temp\pip-build-env-069mgoq7\overlay\Lib\site-packages\mesonbuild\msetup.py", line 394, in run
          app.generate()
        File "C:\Users\Aly\AppData\Local\Temp\pip-build-env-069mgoq7\overlay\Lib\site-packages\mesonbuild\msetup.py", line 190, in generate
          with mesonlib.DirectoryLock(self.build_dir, 'meson-private/meson.lock',
        File "C:\Users\Aly\AppData\Local\Temp\pip-build-env-069mgoq7\overlay\Lib\site-packages\mesonbuild\utils\win32.py", line 22, in __enter__
          mode = msvcrt.LK_LOCK
                 ^^^^^^^^^^^^^^
      AttributeError: module 'msvcrt' has no attribute 'LK_LOCK'

      ERROR: Unhandled python exception

          This is a Meson bug and should be reported!
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.

Notably, the MSVCRT builtins file of GraalPy has a comment saying that it's only there to make Meson work.

[msimacek]

Thanks for the report, I'll add the missing constant

[msimacek]

I made a PR for the msvcrt stuff, which is enough to build matplotlib. But I couldn't build kiwisolver (a runtime dependency of matplotlib). I'm going on a vacation for a few weeks, I'll look into that after I'm back