Fix build. https://bugs.gentoo.org/708066#c8

diff --git a/include/input.h b/include/input.h
index 08a4aee..491c01d 100644
--- a/include/input.h
+++ b/include/input.h
@@ -22,8 +22,6 @@
 #ifndef _INPUT_H
 #define _INPUT_H
 
-char *keyboard_map;
-
 void input_reset(void);
 void input_update(void);
 int input_kstate(int ksym);