package/aircrack-ng: add optional cmocka dependency

cmocka dependency has been added in version 1.3 with
https://github.com/aircrack-ng/aircrack-ng/commit/e3a3a6db30ca99c2473928621a1ba234abcaebf3

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/aircrack-ng/aircrack-ng.mk

@@ -9,6 +9,7 @@ AIRCRACK_NG_SITE = http://download.aircrack-ng.org
 AIRCRACK_NG_LICENSE = GPL-2.0+
 AIRCRACK_NG_LICENSE_FILES = LICENSE
 AIRCRACK_NG_DEPENDENCIES = \
+	$(if $(BR2_PACKAGE_CMOCKA),cmocka) \
 	$(if $(BR2_PACKAGE_LIBNL),libnl) \
 	$(if $(BR2_PACKAGE_OPENSSL),openssl) \
 	$(if $(BR2_PACKAGE_PCRE),pcre) \