There is unnecessary working w/ Tcl interp internals where the API already provided legal forward-compatible (Tcl 8.6) methods to achieve same result.
replace interp->result w/ proper API calls
Hm, I will have to check that - how does this work with Tcl 8.4 or 8.5?
Oh, just checked the patch - yes, this ought to work fine
Implemented the patch - using TCL_STATIC instead of NULL though