Add third party library to Makefile

[efsantana]

I want to use PWM and FreeRTOS on RPi. There are some libraries that do the hard stuff of controlling the RPi's registers, but I can't find how to add them to the Makefile path.

My question is: how do I add any third party library to the Makefile of this project?

[kevinIvan]

That 's accurately my problem. I want to use some library of FreeRTOS on my code in RPi. How could I add them to my project. I go through the FreeRTOS code. I found freeRTOS.h cut there is no implementation of freeRTOS.c.
Any help for resolviing my problem?