From Eggdrop Wiki
As of Eggdrop 1.6.20 the Tcl notifier is replaced by one that handles Eggdrop events and doesn't operate in a seperate thread.
Unfortunately, it's currently buggy if you nest it (vwait/update) under certain conditions and can throw the compilation errors "Tcl_NotifierProcs has no member named initNotifierProc"/"Tcl_NotifierProcs has no member named finalizeNotifierProc" with at least Tcl 8.4 (Current stable Tcl version: 8.6.4)
To disable it:
./configure your bot. Open the config.h file in your editor.
Search for (around line 282)
and replace it with
Carry on with your make config && make && make install. Do not ./configure again, or it'll overwrite config.h