Change netbsd link_name for setlocale

src/unix/mod.rs

@@ -611,6 +611,7 @@ extern {
                   writefds: *mut fd_set,
                   errorfds: *mut fd_set,
                   timeout: *mut timeval) -> ::c_int;
+    #[cfg_attr(target_os = "netbsd", link_name = "__setlocale50")]
     pub fn setlocale(category: ::c_int,
                      locale: *const ::c_char) -> *mut ::c_char;
     pub fn localeconv() -> *mut lconv;