x11/rlaunch: fix build with unsigned char
error[E0308]: mismatched types
--> src/x11.rs:310:54 |
310 | (self.xlib.XLookupString)(&mut keyevent, &mut c_char, 1, null_mut(), null_mut());
| ------------------------- ^^^^^^^^^^^ expected `u8`, found `i8`
| |
| arguments to this function are incorrect
|
= note: expected raw pointer `*mut u8`
found mutable reference `&mut i8`