I am calling for help here, because tried to revert it myself already, but so much has changed since it was first removed (especially in the configure script or config.libs or whatever it was called) that nothing compiled anymore after I tried to fix the conflicts.
Configure scripts are a constant pain when rebasing/reverting etc. because everything touches them.
f04cda523 Revert aa350528: Remove: libtimidity support (NOT timidity support)
c324480c9 Fix: Use sound mixer in libtimidity
673347a7d Codechange: Convert virtual comments to override keywords in libtimidity.h
b00491221 Codechange: Replace NULL with nullptr in libtimidity
Cherry-picking those commits from my PR should apply cleanly on master.