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

verify header includes for sys_uio

See merge request redox-os/relibc!1077

src/header/sys_uio/cbindgen.toml

@@ -1,3 +1,7 @@
+# POSIX header spec: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_uio.h.html
+#
+# 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>."
 sys_includes = ["sys/types.h"]
 include_guard = "_SYS_UIO_H"
 language = "C"