[gpt-oss] Add gpt-oss mxfp4 support

vllm/utils.py

@@ -2908,3 +2908,37 @@ def is_torch_equal_or_newer(target: str) -> bool:
     except Exception:
         # Fallback to PKG-INFO to load the package info, needed by the doc gen.
         return Version(importlib.metadata.version('torch')) >= Version(target)
+
+
+@cache
+def _has_module(module_name: str) -> bool:
+    """Return True if *module_name* can be found in the current environment.
+
+    The result is cached so that subsequent queries for the same module incur
+    no additional overhead.
+    """
+    return importlib.util.find_spec(module_name) is not None
+
+
+def has_pplx() -> bool:
+    """Whether the optional `pplx_kernels` package is available."""
+
+    return _has_module("pplx_kernels")
+
+
+def has_deep_ep() -> bool:
+    """Whether the optional `deep_ep` package is available."""
+
+    return _has_module("deep_ep")
+
+
+def has_deep_gemm() -> bool:
+    """Whether the optional `deep_gemm` package is available."""
+
+    return _has_module("deep_gemm")
+
+
+def has_triton_kernels() -> bool:
+    """Whether the optional `triton_kernels` package is available."""
+
+    return _has_module("triton_kernels")