Incorrect GO4K_FSTG_ID when exporting songs that don't use glitch

[vsariola]

Working on the current master branch.

When exporting a song with a global store and without a glitch, in the exported .inc file GO4K_FSTG_ID is set to 13 but should be 12, because there is no glitch op code and thus _go4kFSTG_func is at index 12 in the go4k_synth_commands table. See here

The 'else' branch (that adds filler in case glitch is not used) was removed on purpose to maintain compatibility with pre-glitch songs, but the current exporter always exports GO4K_FSTG_ID as 13.

The 4klang.asm version in Go4kVSTI/win directory works by adding the filler but in the process breaks compatibility.

Short term solution is to export GO4K_FSTG_ID as 12 if glitch is not used, and 13 if glitch is used.

However, would it be possible to not include the function pointers in the go4k_synth_commands in case a particular unit is not used? This should even save a few bytes, right? And then give all units IDs accordingly in a running manner in the exported .inc file, in case the unit was used.