Add ability to change AT keyboard scancode and disable translation. Fixes keyboard in Solaris 8.

src/keyboard.h

@@ -4,3 +4,12 @@ void keyboard_process();
 extern int keyboard_scan;
 
 extern uint8_t pcem_key[272];
+
+enum
+{
+        SCANCODE_SET_1,
+        SCANCODE_SET_2,
+        SCANCODE_SET_3
+};
+
+void keyboard_set_scancode_set(int set);