Auto merge of #3145 - coolreader18:redox-locale, r=JohnTitor

Add LC_ constants for redox (and truncate() is now supported)

From `relibc/include/bits/locale.h` and `relibc/src/header/unistd/mod.rs`

src/unix/mod.rs

@@ -1048,6 +1048,7 @@ extern "C" {
 
     pub fn symlink(path1: *const c_char, path2: *const c_char) -> ::c_int;
 
+    pub fn truncate(path: *const c_char, length: off_t) -> ::c_int;
     pub fn ftruncate(fd: ::c_int, length: off_t) -> ::c_int;
 
     pub fn signal(signum: ::c_int, handler: sighandler_t) -> sighandler_t;
@@ -1447,7 +1448,6 @@ cfg_if! {
     if #[cfg(not(target_os = "redox"))] {
         extern {
             pub fn getsid(pid: pid_t) -> pid_t;
-            pub fn truncate(path: *const c_char, length: off_t) -> ::c_int;
             #[cfg_attr(all(target_os = "macos", target_arch = "x86"),
                        link_name = "pause$UNIX2003")]
             pub fn pause() -> ::c_int;

src/unix/redox/mod.rs

@@ -459,6 +459,15 @@ pub const O_SYMLINK: ::c_int = 0x4000_0000;
 // FIXME: Fix negative values missing from includes
 pub const O_NOFOLLOW: ::c_int = -0x8000_0000;
 
+// locale.h
+pub const LC_ALL: ::c_int = 0;
+pub const LC_COLLATE: ::c_int = 1;
+pub const LC_CTYPE: ::c_int = 2;
+pub const LC_MESSAGES: ::c_int = 3;
+pub const LC_MONETARY: ::c_int = 4;
+pub const LC_NUMERIC: ::c_int = 5;
+pub const LC_TIME: ::c_int = 6;
+
 // netdb.h
 pub const AI_PASSIVE: ::c_int = 0x0001;
 pub const AI_CANONNAME: ::c_int = 0x0002;
@@ -502,6 +511,7 @@ pub const IP_MULTICAST_TTL: ::c_int = 33;
 pub const IP_MULTICAST_LOOP: ::c_int = 34;
 pub const IP_ADD_MEMBERSHIP: ::c_int = 35;
 pub const IP_DROP_MEMBERSHIP: ::c_int = 36;
+pub const IPPROTO_RAW: ::c_int = 255;
 // }
 
 // netinet/tcp.h