diff --git a/src/header/strings/cbindgen.toml b/src/header/strings/cbindgen.toml
index 4479f685d6..c51b12a496 100644
--- a/src/header/strings/cbindgen.toml
+++ b/src/header/strings/cbindgen.toml
@@ -4,12 +4,12 @@
 # - "The <strings.h> header shall define the locale_t type as described in <locale.h>."
 # - "The <strings.h> header shall define the size_t type as described in <sys/types.h>."
 #
-# sys/types.h gets size_t from stddef.h (just include stddef.h here instead of importing all of sys/types.h)
 # features.h required for deprecated annotations
-sys_includes = ["features.h", "stddef.h"]
+sys_includes = ["features.h"]
 include_guard = "_RELIBC_STRINGS_H"
 after_includes = """
 #include <bits/locale-t.h> // for locale_t from locale.h
+#include <bits/size-t.h>   // for size_t from sys/types.h
 """
 language = "C"
 style = "Tag"