Add missing headers for compilation on x86 targets

Change-Id: I5f4dc797b353a0f01fa00d38375ec303bf863254
diff --git a/init/keychords.c b/init/keychords.c
index 53ab391..892cbdf 100644
--- a/init/keychords.c
+++ b/init/keychords.c
@@ -17,9 +17,11 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <linux/keychord.h>
+#include <unistd.h>
 
 #include "init.h"
 #include "log.h"