diff --git a/go/ssa/interp/external.go b/go/ssa/interp/external.go
index 788f02ae..0e3de617 100644
--- a/go/ssa/interp/external.go
+++ b/go/ssa/interp/external.go
@@ -237,21 +237,6 @@ func ext۰math۰Log(fr *frame, args []value) value {
 	return math.Log(args[0].(float64))
 }
 
-func ext۰os۰Pipe(fr *frame, args []value) value {
-	// This is an inlining of linux's os.Pipe.
-	// func os.Pipe() (r *File, w *File, err error)
-	var p [2]int
-	if err := syscall.Pipe2(p[:], syscall.O_CLOEXEC); err != nil {
-		// TODO(adonovan): fix: return an *os.SyscallError.
-		return tuple{nil, nil, wrapError(err)}
-	}
-
-	NewFile := fr.i.prog.ImportedPackage("os").Func("NewFile")
-	r := call(fr.i, fr, 0, NewFile, []value{uintptr(p[0]), "|0"})
-	w := call(fr.i, fr, 0, NewFile, []value{uintptr(p[1]), "|1"})
-	return tuple{r, w, wrapError(nil)}
-}
-
 func ext۰os۰runtime_args(fr *frame, args []value) value {
 	return fr.i.osArgs
 }
diff --git a/go/ssa/interp/external_unix.go b/go/ssa/interp/external_unix.go
index c482eabb..be125866 100644
--- a/go/ssa/interp/external_unix.go
+++ b/go/ssa/interp/external_unix.go
@@ -8,6 +8,22 @@ package interp
 
 import "syscall"
 
+func ext۰os۰Pipe(fr *frame, args []value) value {
+	// func os.Pipe() (r *File, w *File, err error)
+
+	// The portable POSIX pipe(2) call is good enough for our needs.
+	var p [2]int
+	if err := syscall.Pipe(p[:]); err != nil {
+		// TODO(adonovan): fix: return an *os.SyscallError.
+		return tuple{nil, nil, wrapError(err)}
+	}
+
+	NewFile := fr.i.prog.ImportedPackage("os").Func("NewFile")
+	r := call(fr.i, fr, 0, NewFile, []value{uintptr(p[0]), "|0"})
+	w := call(fr.i, fr, 0, NewFile, []value{uintptr(p[1]), "|1"})
+	return tuple{r, w, wrapError(nil)}
+}
+
 func fillStat(st *syscall.Stat_t, stat structure) {
 	stat[0] = st.Dev
 	stat[1] = st.Ino
diff --git a/go/ssa/interp/external_windows.go b/go/ssa/interp/external_windows.go
index ef28a371..24d1a876 100644
--- a/go/ssa/interp/external_windows.go
+++ b/go/ssa/interp/external_windows.go
@@ -6,6 +6,9 @@ package interp
 
 import "syscall"
 
+func ext۰os۰Pipe(fr *frame, args []value) value {
+	panic("os.Pipe not yet implemented")
+}
 func ext۰syscall۰Close(fr *frame, args []value) value {
 	panic("syscall.Close not yet implemented")
 }