Add Jansson (required for Samba now)

[Douglas R. Reno]

Samba added a hard requirement of Jansson for their RPC functionality, used to access SMB shares (which is the base functionality of the program).

Jansson is just CMMI, and is used in the following packages:

grep -r jansson *
gnome/applications/network-manager-applet.xml:      <ulink url="http://www.digip.org/jansson/">Jansson</ulink> (for the team configuration editor)
networking/netutils/networkmanager.xml:      <ulink url="http://www.digip.org/jansson/">Jansson</ulink>,
networking/netlibs/nghttp2.xml:      <ulink url="http://www.digip.org/jansson/">Jansson</ulink>, <!--required
networking/netprogs/samba.xml:      <ulink url="http://www.digip.org/jansson/">Jansson</ulink>,

I know for NetworkManager, it's used for teams support (useful for Qemu VMs and other enterprise networking setups).

Looking at their release methodology, it seems like it gets a new release twice a year (if that).

[Douglas R. Reno]

Added at r20535