So here it is the path to configure the library that I was missing for my code to compile. Basic but if you don't know can be annoying.
right cklick on the project in the
project explorer -> properties
-> c/c++ build
ONCE you are in the C/C++ Build settings. you proceed like this:
c/c++ build -> Settings -> linker -> libraries -> add
-> pthread ->
once you add the library you click OK and Rebuild
ok -> rebuild
That should do the trick for: pthread_create and the such.