fix windows again

Author: cobbal

Sources/swsh/FDWrapperCommand.swift

@@ -72,10 +72,11 @@ internal class FDWrapperCommand: Command {
             return .success(fdMap: [dstFd: io.fileDescriptor], ref: io)
             #else
             */
-            var pmode: mode_t = 0o666
             #if os(Windows)
-            pmode = mode_t(_S_IREAD | _S_IWRITE)
+            let pmode: Int32 = _S_IREAD | _S_IWRITE
             let path = path == "/dev/null" ? "NUL" : path
+            #else
+            let pmode: mode_t = 0o666
             #endif
             printOSCall("open", path, oflag, pmode)
             let fd = open(path, oflag, pmode)