Linking a new source file

[Sergej Perschin]

Hello,

I am trying to understand, how to correctly link a new source file.
My problem is the following:
I created a new source file in stdlib and added it to the routines and
headers in the Makefile inside stdlib. The file includes semaphore.h but I
get undefined reference errors for sem_init(), sem_wait() and sem_post().
What can I do to use these functions?

Best Regards