Merge branch 'eliminate-timeval-function' into 'master'

eliminate cbindgen export function workaround for timeval struct

See merge request redox-os/relibc!1279

src/header/bits_timeval/cbindgen.toml

@@ -5,7 +5,8 @@
 # POSIX headers that require timeval:
 # - sys/resource.h
 # - sys/select.h (where it should be defined)
-# - sys/time.h
+# - sys/time.h (previous POSIX versions defined it here)
+# - utmpx.h (TODO: not currently present in relibc)
 after_includes = """
 #include <bits/time-t.h>
 #include <bits/suseconds-t.h>
@@ -18,3 +19,6 @@ cpp_compat = true
 
 [enum]
 prefix_with_name = true
+
+[export]
+include = ["timeval"]

src/header/bits_timeval/mod.rs

@@ -13,6 +13,3 @@ pub struct timeval {
     pub tv_sec: time_t,
     pub tv_usec: suseconds_t,
 }
-
-#[unsafe(no_mangle)]
-pub unsafe extern "C" fn cbindgen_export_timeval(_: timeval) {}