diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index 2089285..99bbc3e 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -35,16 +35,23 @@
     "__kernel_old_timeval": "1",
     }
 
-# this is the set of known kernel data structures we want to remove from
-# the final headers
-kernel_structs_to_remove = set(
-        [
-          # Remove the structures since they are still the same as
-          # timeval, itimerval.
-          "__kernel_old_timeval",
-          "__kernel_old_itimerval",
-        ]
-    )
+# This is the set of known kernel data structures we want to remove from
+# the final headers. If the map value is False, that means that in
+# addition to removing the structure, add an #include <bits/STRUCT.h>
+# to the file.
+kernel_structs_to_remove = {
+    # Remove the structures since they are still the same as
+    # timeval, itimerval.
+    "__kernel_old_timeval": True,
+    "__kernel_old_itimerval": True,
+    # Replace all of the below structures with #include <bits/STRUCT.h>
+    "epoll_event": False,
+    "flock": False,
+    "flock64": False,
+    "in_addr": False,
+    "ip_mreq_source": False,
+    "ip_msfilter": False,
+    }
 
 # define to true if you want to remove all defined(CONFIG_FOO) tests
 # from the clean headers. testing shows that this is not strictly necessary
@@ -100,20 +107,6 @@
     }
 
 
-# This is the set of struct definitions that we want to replace with
-# a #include of <bits/struct.h> instead.
-kernel_struct_replacements = set(
-        [
-          "epoll_event",
-          "flock",
-          "flock64",
-          "in_addr",
-          "ip_mreq_source",
-          "ip_msfilter",
-        ]
-    )
-
-
 # This is the set of known static inline functions that we want to keep
 # in the final kernel headers.
 kernel_known_generic_statics = set(