Running Azure IoT sdk-c

I am not linking the library at the moment but including the source of the libuuid.
If you know which library is providing these functions from the existing image:
uuid_generate' uuid_unparse’
I could link the library instead as I have done with ssl and crypto, but I am not even sure if these are included in the build image.

What I have done was to include the libuuid into the source directly, but then I get the error:

error “System with usleep() or nanosleep() required!

where the usleep and nanosleep should be included in the time.c, so I guess I need to link this library so the compiler finds it?
Do you know which one of the image`s libraries is including this?