remove unsigned char * warning with gcc 4.0
diff --git a/include/ebtables_u.h b/include/ebtables_u.h
index 25f3fbb..f1f1dfd 100644
--- a/include/ebtables_u.h
+++ b/include/ebtables_u.h
@@ -292,9 +292,9 @@
void ebt_check_option(unsigned int *flags, unsigned int mask);
#define ebt_check_inverse(arg) _ebt_check_inverse(arg, argc, argv)
int _ebt_check_inverse(const char option[], int argc, char **argv);
-void ebt_print_mac(const char *mac);
-void ebt_print_mac_and_mask(const char *mac, const char *mask);
-int ebt_get_mac_and_mask(char *from, char *to, char *mask);
+void ebt_print_mac(const unsigned char *mac);
+void ebt_print_mac_and_mask(const unsigned char *mac, const unsigned char *mask);
+int ebt_get_mac_and_mask(const char *from, unsigned char *to, unsigned char *mask);
void ebt_parse_ip_address(char *address, uint32_t *addr, uint32_t *msk);
char *ebt_mask_to_dotted(uint32_t mask);