split out timeval to reduce namespace pollution

src/header/bits_timeval/mod.rs

@@ -0,0 +1,15 @@
+use crate::platform::types::{suseconds_t, time_t};
+
+/// See <https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_select.h.html>.
+///
+/// Note that the `timeval` struct was specified for
+/// [`sys/time.h`](crate::header::sys_time) in the Open Group Base
+/// Specifications Issue 7 and prior, see
+/// <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_time.h.html>.
+#[repr(C)]
+#[allow(non_camel_case_types)]
+#[derive(Default)]
+pub struct timeval {
+    pub tv_sec: time_t,
+    pub tv_usec: suseconds_t,
+}