libzint isn't found even when installed

[fogti]

https://github.com/pablo-s/passes/blob/d151ab2043bd25b76335743c5b8c3fc072f8ecb6/src/model/meson.build#L3

I installed (lib)zint on freebsd, which even installs cmake config files, but it isn't found unless I change the line above to

libzint = dependency('zint')