ENH: Globally enable Cython free-threading directive

This is the Cython equivalent of adding a `Py_mod_gil` slot with
`Py_MOD_GIL_NOT_USED` like we did in pandas-dev#59135.

Author: lysnikolaou

meson.build

@@ -44,6 +44,11 @@ else
     meson.add_dist_script(py, versioneer, '-o', '_version_meson.py')
 endif
 
+cy = meson.get_compiler('cython')
+if cy.version().version_compare('>=3.1.0')
+  add_global_arguments('-Xfreethreading_compatible=true', language : 'cython')
+endif
+
 # Needed by pandas.test() when it looks for the pytest ini options
 py.install_sources(
     'pyproject.toml',