We need to tell Cabal that WinCBindings is a module of the timeout program

testsuite/timeout/timeout.cabal

@@ -15,6 +15,7 @@ cabal-version: >=1.2
 
 Executable timeout
     Main-Is: timeout.hs
+    Other-Modules: WinCBindings
     Extensions: CPP
     Build-Depends: base, process
     if os(windows)