package/capnproto: add openssl optional dependency

openssl is an optional dependency that is enabled by default since
version 0.7.0 and
https://github.com/capnproto/capnproto/commit/23db5e3fd91104a0b2881d8f8ab3c10bf9dd8e75

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

package/capnproto/capnproto.mk

@@ -21,5 +21,12 @@ endif
 # The actual source to be compiled is within a 'c++' subdirectory
 CAPNPROTO_SUBDIR = c++
 
+ifeq ($(BR2_PACKAGE_OPENSSL),y)
+CAPNPROTO_CONF_OPTS += --with-openssl
+CAPNPROTO_DEPENDENCIES += openssl
+else
+CAPNPROTO_CONF_OPTS += --without-openssl
+endif
+
 $(eval $(autotools-package))
 $(eval $(host-autotools-package))