It may well be that Mike's BASIC is embedded amongst Arduino code so might be difficult to modularise as you say. I have no idea how much work it takes to add or remove a library.
Doing it in Visual Basic I would just scan through the check boxes on the user interface and create a file with all the necesary includes and defines then run the build process by calling a batch file of some sort.
I don't know how to do that in HTML and I appreciate that there might be server costs that would make it unworkable.
The IR change that I made was virtually just one byte in the NEC receive section. Since it is a library and no one else seems to have had a problem I assume that it is specific to my devices and would not know where to make the suggestion anyway - Github is another unknown area with dragons...