Add 312 metadata and example cythonize command

line_profiler/_line_profiler.pyx

@@ -1,6 +1,18 @@
-#cython: language_level=3
-"""
+# cython: language_level=3
+# cython: infer_types=True
+# distutils: language=c++
+# distutils: include_dirs = python25.pxd
+r"""
 This is the Cython backend used in :py:mod:`line_profiler.line_profiler`.
+
+Ignore:
+    
+    # Standalone compile instructions for developers 
+    # Assuming the cwd is the repo root.
+    cythonize --annotate --inplace \
+        ./line_profiler/_line_profiler.pyx \
+        ./line_profiler/timers.c \
+        ./line_profiler/unset_trace.c
 """
 from .python25 cimport PyFrameObject, PyObject, PyStringObject
 from sys import byteorder

pyproject.toml

@@ -1,7 +1,7 @@
 [build-system]
 requires = [
     "setuptools>=41.0.1",
-    "Cython==3.0.0a11            ; python_version < '4.0'  and python_version >= '3.12' ",
+    "Cython>=3.0.3; python_version < '4.0'  and python_version >= '3.12' ",
     "Cython>=0.29.24,<=3.0.0a11  ; python_version < '3.12' ",
 ]
 build-backend = "setuptools.build_meta"  # comment out to disable pep517
@@ -32,7 +32,8 @@ omit =[
 ]
 
 [tool.cibuildwheel]
-build = "cp36-* cp37-* cp38-* cp39-* cp310-* cp311-*"
+#build = "cp36-* cp37-* cp38-* cp39-* cp310-* cp311-* cp312-*"
+build = "cp312-*"
 build-frontend = "build"
 build-verbosity = 1
 test-requires = [ "-r requirements/tests.txt",]

setup.py

@@ -290,6 +290,7 @@ def run_cythonize(force=False):
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: 3.11',
+        'Programming Language :: Python :: 3.12',
         'Programming Language :: Python :: Implementation :: CPython',
         'Topic :: Software Development',
     ]