Support Py_UNUSED() on clang (GH-13544)
diff --git a/Include/pymacro.h b/Include/pymacro.h
index 546f9c6..1890619 100644
--- a/Include/pymacro.h
+++ b/Include/pymacro.h
@@ -89,10 +89,15 @@
/* Check if pointer "p" is aligned to "a"-bytes boundary. */
#define _Py_IS_ALIGNED(p, a) (!((uintptr_t)(p) & (uintptr_t)((a) - 1)))
-#ifdef __GNUC__
-#define Py_UNUSED(name) _unused_ ## name __attribute__((unused))
+/* Use this for unused arguments in a function definition to silence compiler
+ * warnings. Example:
+ *
+ * int func(int a, int Py_UNUSED(b)) { return a; }
+ */
+#if defined(__GNUC__) || defined(__clang__)
+# define Py_UNUSED(name) _unused_ ## name __attribute__((unused))
#else
-#define Py_UNUSED(name) _unused_ ## name
+# define Py_UNUSED(name) _unused_ ## name
#endif
#define Py_UNREACHABLE() abort()