[Build] Cython compilation support fix (#14296)

Signed-off-by: Gregory Shtrasberg <Gregory.Shtrasberg@amd.com>

tests/build_cython.py

@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: Apache-2.0
+import Cython.Compiler.Options
+from Cython.Build import cythonize
+from setuptools import setup
+
+Cython.Compiler.Options.annotate = True
+
+infiles = []
+
+infiles += [
+    "vllm/engine/llm_engine.py",
+    "vllm/transformers_utils/detokenizer.py",
+    "vllm/engine/output_processor/single_step.py",
+    "vllm/outputs.py",
+    "vllm/engine/output_processor/stop_checker.py",
+]
+
+infiles += [
+    "vllm/core/scheduler.py",
+    "vllm/sequence.py",
+    "vllm/core/block_manager.py",
+]
+
+infiles += [
+    "vllm/model_executor/layers/sampler.py",
+    "vllm/sampling_params.py",
+    "vllm/utils.py",
+]
+
+setup(ext_modules=cythonize(infiles,
+                            annotate=False,
+                            force=True,
+                            compiler_directives={
+                                'language_level': "3",
+                                'infer_types': True
+                            }))
+
+# example usage: python3 build_cython.py build_ext --inplace