External libraries

I want to use external libraries (with sources). What will be the best practice for including them?

Copy to /cocos/external? Where do I include the reference to the new library (mainly linux desktop - iOS and Android are done).

wouldn’t you be more comfortable by adding c++ library sources within your project itself?

Hmm. Good question. That’s why I asked for best practices. I have no experiences yet.

Surely adding them to your sources would spare you from a complicated integration, multiplied by every different system you have to bind them. One for ios, another for android…
Integrating in the build system is a valid practice, but not mandatory; while letting them into the code directly is surely faster…