diff --git a/src/header/bits_iovec/cbindgen.toml b/src/header/bits_iovec/cbindgen.toml
index 0a09ebf02a..55b079d8a4 100644
--- a/src/header/bits_iovec/cbindgen.toml
+++ b/src/header/bits_iovec/cbindgen.toml
@@ -5,9 +5,10 @@
 # POSIX headers that require iovec:
 # - sys/socket.h
 # - sys/uio.h (where it should be defined)
-#
-# sys/types.h included for c_void and size_t
-sys_includes = ["sys/types.h"]
+sys_includes = []
+after_includes = """
+#include <bits/size-t.h> // for size_t from sys/types.h
+"""
 include_guard = "_RELIBC_BITS_IOVEC_H"
 language = "C"
 style = "Tag"
diff --git a/src/header/sys_uio/cbindgen.toml b/src/header/sys_uio/cbindgen.toml
index f24e59d38a..8e6ede28bb 100644
--- a/src/header/sys_uio/cbindgen.toml
+++ b/src/header/sys_uio/cbindgen.toml
@@ -3,8 +3,15 @@
 # Spec quotations relating to includes:
 # - "The <sys/uio.h> header shall define the ssize_t and size_t types as described in <sys/types.h>."
 #
-# bits/iovec.h brings in sys/types.h
-sys_includes = ["bits/iovec.h"]
+# bits/iovec.h brings in size_t
+sys_includes = []
+after_includes = """
+#include <bits/ssize-t.h> // for ssize_t from sys/types.h
+#include <bits/iovec.h>   // for iovec
+
+// for Non-POSIX functions preadv and pwritev
+#include <bits/off-t.h>   // for off_t from sys/types.h
+"""
 include_guard = "_RELIBC_SYS_UIO_H"
 language = "C"
 style = "Tag"