diff --git a/src/header/regex/cbindgen.toml b/src/header/regex/cbindgen.toml
index fa1c711c04..8c3b2a54e0 100644
--- a/src/header/regex/cbindgen.toml
+++ b/src/header/regex/cbindgen.toml
@@ -2,7 +2,10 @@
 #
 # Spec quotations relating to includes:
 # - "The <regex.h> header shall define the size_t type as described in <sys/types.h>."
-sys_includes = ["sys/types.h"]
+sys_includes = []
+after_includes = """
+#include <bits/size-t.h> // for size_t from sys/types.h
+"""
 include_guard = "_RELIBC_REGEX_H"
 language = "C"
 style = "Type"