Merge branch 'verify-sysun-includes' into 'master'

verify sys_un header includes

See merge request redox-os/relibc!1195

src/header/sys_un/cbindgen.toml

@@ -1,5 +1,12 @@
-sys_includes = ["sys/socket.h"]
-include_guard = "_SYS_UN_H"
+# POSIX header spec: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_un.h.html
+#
+# Spec quotations relating to includes:
+# - "The <sys/un.h> header shall define the sa_family_t type as described in <sys/socket.h>."
+sys_includes = []
+after_includes = """
+#include <bits/safamily-t.h> // for sa_family_t from sys/socket.h
+"""
+include_guard = "_RELIBC_SYS_UN_H"
 language = "C"
 style = "Tag"
 no_includes = true