term: fix vlib/term/termios/termios_test.v on windows

vlib/term/termios/termios_test.v

@@ -1,5 +1,20 @@
 module termios
 
+fn test_portable() {
+	assert 123 == int(flag(123))
+	o := Termios{
+		c_lflag: flag(0xFFFF)
+	} // assume c_lflag exists everywhere
+	// dump( o.c_lflag )
+	mut n := o
+	n.c_lflag &= invert(1)
+	// dump( n.c_lflag )
+	assert n.c_lflag != o.c_lflag
+	n.disable_echo() // just assume it exists, and can be called everywhere
+	assert true
+}
+
+[if !windows]
 fn test_termios() {
 	mut original_term := Termios{}
 	tcgetattr(0, mut original_term)

vlib/term/termios/termios_windows.c.v

@@ -27,6 +27,15 @@ pub fn invert(value TcFlag) TcFlag {
 }
 
 pub struct Termios {
+pub mut:
+	c_iflag  TcFlag
+	c_oflag  TcFlag
+	c_cflag  TcFlag
+	c_lflag  TcFlag
+	c_line   Cc
+	c_cc     [32]Cc
+	c_ispeed Speed
+	c_ospeed Speed
 }
 
 // tcgetattr is an unsafe wrapper around C.termios and keeps its semantic