Merge pull request #43 from MggMuggins/master

Imp va_arg for fcntl; fcntl test

src/fcntl/src/lib.rs

@@ -37,7 +37,7 @@ pub extern "C" fn creat(path: *const c_char, mode: mode_t) -> c_int {
 }
 
 #[no_mangle]
-pub extern "C" fn fcntl(fildes: c_int, cmd: c_int, arg: c_int) -> c_int {
+pub extern "C" fn sys_fcntl(fildes: c_int, cmd: c_int, arg: c_int) -> c_int {
     platform::fcntl(fildes, cmd, arg)
 }