fix wasm build

Author: sfackler

src/libstd/sys/wasm/pipe.rs

@@ -12,6 +12,10 @@ impl AnonPipe {
         match self.0 {}
     }
 
+    pub fn is_read_vectored(&self) -> bool {
+        match self.0 {}
+    }
+
     pub fn write(&self, _buf: &[u8]) -> io::Result<usize> {
         match self.0 {}
     }
@@ -20,6 +24,10 @@ impl AnonPipe {
         match self.0 {}
     }
 
+    pub fn is_write_vectored(&self) -> bool {
+        match self.0 {}
+    }
+
     pub fn diverge(&self) -> ! {
         match self.0 {}
     }