split out timer_t from sys_types

src/header/bits_timer-t/cbindgen.toml

@@ -0,0 +1,17 @@
+# POSIX header spec: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/sys_types.h.html
+#
+# This type is split out to prevent importing all of sys/types.h into other headers.
+#
+# POSIX headers that require timer_t:
+# - sys/types.h (where it should be defined)
+# - time.h
+sys_includes = []
+include_guard = "_RELIBC_BITS_TIMER_T_H"
+language = "C"
+style = "type"
+no_includes = true
+cpp_compat = true
+[export]
+include = ["timer_t"]
+[enum]
+prefix_with_name = true

src/header/bits_timer-t/mod.rs

@@ -0,0 +1,5 @@
+use crate::platform::types::c_void;
+
+/// Used for timer ID returned by timer_create()
+#[allow(non_camel_case_types)]
+pub type timer_t = *mut c_void;