package/zynaddsubfx: add jack{1, 2} optional dependency
jack{1,2} is an optional dependency (enabled by default) since the
addition of the package in commit
18a863063735e2c658fa6947a4e540e9dda6c431
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 3bcedaa732b539e4ad32776e867ef9626ffca5b7)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>