I have a KMP library, and after adding compose mp I had to disable watchOS (compose has to be define in common and they have no watchOS implementation or stubs). Is there a cradle way to something like a #define for WITH_COMPOSE or without and then build twice - once for compose included and once without?

If I got you right, you could just check some project property you define. Build scripts are fully turing completed, so you can just use

if

for example.