Issue #18722: Remove uses of the "register" keyword in C code.
diff --git a/Objects/stringlib/split.h b/Objects/stringlib/split.h
index 947dd28..31f77a7 100644
--- a/Objects/stringlib/split.h
+++ b/Objects/stringlib/split.h
@@ -345,8 +345,8 @@
        and the appends only done when the prealloc buffer is full.
        That's too much work for little gain.*/
 
-    register Py_ssize_t i;
-    register Py_ssize_t j;
+    Py_ssize_t i;
+    Py_ssize_t j;
     PyObject *list = PyList_New(0);
     PyObject *sub;