I’ve just realized that in cocos2d-x 3.15 (previously using 3.14.1) there’s no prebuilt-mk directory in cocos directory. That’s why I probably can’t build prebuilt libraries…
Hmm, and what happening when you executing this for example?
cocos gen-libs -p mac
Well it starts building, but I’m getting an error:
cocos gen-libs -p android --app-abi armeabi-v7a
make: *** No rule to make target `/Users/piotr/Documents/pierdoly/cocos2d-x-3.14/external/tremolo/Tremolo/bitwise.c', needed by `obj/local/armeabi-v7a/objs/vorbisidec/Tremolo/bitwise.o'. Stop.
make: *** Waiting for unfinished jobs....
Error running command, return code: 2.
Error running command, return code: 14.
I though I have to add tremolo in prebuilt-mk, but it’s missing.
The problem is I have cocos2d-x 3.14.1 with my own adjustments (new audioengine as well). I’ve found some new bug fixes in audio so I’ve replaced cocos/audio with the new one and now I’m stuck, because I cannot compile it 
I can’t move to 3.15 yet due to my adjustments (I don’t remember where I did them).
Ok I figured it out. tremolo and pvmp3dev were moved to android-specific directory. However somewhere in makefiles (cannot find where) there’s still a path without android-specific subdirectory.
Yes, typical problem with modified version
I remove the whole proj.android-studio/app/obj directory to fix this problem