Declare free-threaded support and support 3.13t

Author: ngoldbaum

.github/workflows/smoke.yml

@@ -34,6 +34,7 @@ jobs:
       fail-fast: false
       matrix:
         config:
+          - {os: ubuntu-24.04, python: "3.14t", ffmpeg: "8.0", extras: true}
           - {os: ubuntu-24.04, python: "3.12", ffmpeg: "8.0", extras: true}
           - {os: ubuntu-24.04, python: "pypy3.10", ffmpeg: "8.0"}
           - {os: macos-14, python: "3.9", ffmpeg: "8.0"}
@@ -50,6 +51,7 @@ jobs:
       uses: actions/setup-python@v5
       with:
         python-version: ${{ matrix.config.python }}
+        allow-prereleases: true
 
     - name: OS Packages
       run: |

.github/workflows/tests.yml

@@ -65,6 +65,7 @@ jobs:
           CIBW_SKIP: "pp*"
           CIBW_TEST_COMMAND: mv {project}/av {project}/av.disabled && python -m pytest {package}/tests && mv {project}/av.disabled {project}/av
           CIBW_TEST_REQUIRES: pytest numpy
+          CIBW_ENABLE: cpython-freethreading
         run: |
           pip install cibuildwheel delvewheel
           cibuildwheel --output-dir dist

setup.py

@@ -150,6 +150,7 @@ def parse_cflags(raw_flags):
     "embedsignature": True,
     "binding": False,
     "language_level": 3,
+    "freethreading_compatible": True,
 }
 
 # Add the cythonized loudnorm extension to ext_modules