xfail tests that are currently failing on windows, reported in #7999

src/test/run-pass/issue-3168.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 // xfail-fast
+// xfail-win32 #7999
 
 use std::comm;
 use std::task;

src/test/run-pass/issue-3176.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 // xfail-fast
+// xfail-win32 #7999
 
 use std::comm::{Select2, Selectable};
 use std::comm;

src/test/run-pass/pipe-sleep.rs

@@ -11,6 +11,7 @@
 // except according to those terms.
 
 // xfail-test needs sleep
+// xfail-win32 #7999
 
 extern mod extra;
 

src/test/run-pass/unit-like-struct-drop-run.rs

@@ -10,6 +10,7 @@
 
 // Make sure the destructor is run for unit-like structs.
 // xfail-fast
+// xfail-win32 #7999
 
 use std::task;