Enable piping on Windows

examples/pipe.c

@@ -3,13 +3,9 @@
 
 int main(void)
 {
-#if _WIN32
-    WARN("Piping is not implemented on Windows yet");
-#else
     CHAIN(IN(PATH("examples", "pipe.c")),
           CHAIN_CMD(PATH("tools", "rot13")),
           CHAIN_CMD(PATH("tools", "hex")));
-#endif
 
     return 0;
 }