[sfont~] crashes Pd Vanilla if no SoundFont loaded

[joe-rouen]

If no soundfont is loaded into [sfont~], changing PC/CH or BK/CH is leading to crash / force closing Pd Vanilla. Simple test can be done with the 'sfont~-help.pd' patch by removing 'sf/waves.sf2' from 'else/sfont~ -v -ch 32 sf/waves.sf2'.

Current workaround: Add glue for checking if an SF2 file has been loaded by [sfont~] before allowing any traffic to its Inlet 0. Thanks.