Include <stdlib.h> for malloc() and free()

host/main.c

@@ -19,6 +19,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
 #include <time.h>