Fixup last commit

src/header/stdio/mod.rs

@@ -1053,7 +1053,7 @@ pub unsafe extern "C" fn setbuf(stream: *mut FILE, buf: *mut c_char) {
 /// Set buffering of `stream` to line buffered
 #[no_mangle]
 pub unsafe extern "C" fn setlinebuf(stream: *mut FILE) {
-    setvbuf(stream, NULL, _IOLBF, 0);
+    setvbuf(stream, ptr::null_mut(), _IOLBF, 0);
 }
 
 /// Reset `stream` to use buffer `buf` of size `size`