Switched from raw input to low-level keyboard hook, with -W/--raw to optionally re-enable raw input (needed to debug, so the hook doesn't cause GDB to make system input unusably slow), fixes #4399.

src/include/86box/86box.h

@@ -165,6 +165,7 @@ extern _Atomic double mouse_y_error;        /* Mouse error accumulator - Y */
 #endif
 extern int    pit_mode;                     /* (C) force setting PIT mode */
 extern int    fm_driver;                    /* (C) select FM sound driver */
+extern int    raw_input;                    /* (C) Use raw input */
 
 /* Keyboard variables for future key combination redefinition. */
 extern uint16_t key_prefix_1_1;