TimerFreeTone Library v1.5: Play tones without timers and therefore no conflicts

jirm:
Good day.

I`m a happy user that your nice TimerFreeTone libray for years with several esp8266 projects, but now I need to update ESP core to lastest 2.4.2 release and your library seems have issues to compile propperly.
When I try to compile arduino IDE raise several errors about it:

Sounds like you don't have something setup correctly with the 2.4.2 release as TimerFreeTone isn't doing anything complicated that would fail almost totally like that.

Tim