Actually, just pass control keys...

If the codepage tables have holes where US-ASCII chars go, don't
send the character under the assumption that it won't be on the
keyboard (and certainly not in the "same" place).

src/conio/win32gdi.c

@@ -359,8 +359,11 @@ gdi_handle_wm_char(WPARAM wParam, LPARAM lParam)
 		cp = wParam;
 	}
 	// Translate from unicode to codepage...
-	ch = cpchar_from_unicode_cpoint(getcodepage(), cp, cp);
-	if (ch && ch < 256) {
+	ch = cpchar_from_unicode_cpoint(getcodepage(), cp, 0);
+	// Control characters get a pass (TODO: Test in ATASCII)
+	if (ch == 0 && cp < 32)
+		ch = cp;
+	if (ch) {
 		for (i = 0; i < repeat; i++)
 			gdi_add_key(ch);
 	}