A minor issue that's a Werror I guess:
/tmp/homebrew-avidemux3-2.6-Cl9X/avidemux_core/ADM_coreScriptQt/src/SegmentCollection.cpp:58:12: error: comparison of unsigned expression < 0 is always false
[-Werror,-Wtautological-compare]
if ((pos < 0) || (pos >= this->_editor->getNbSegment()))
~~~ ^ ~
1 error generated.
make[2]: *** [ADM_coreScriptQt/src/CMakeFiles/ADM_coreScriptQt.dir/SegmentCollection.cpp.o] Error 1
make[1]: *** [ADM_coreScriptQt/src/CMakeFiles/ADM_coreScriptQt.dir/all] Error 2
make: *** [all] Error 2