The components are build independently and then are linked with main module corresponding to target platform.
Core is supposed to be platform-independent, while libc and plugins are dependent on specific architecture / platform.
The commit disables unit tests building and running during precommit.
That is supposed to be fixed in a subsequent commit.
Also, the commit disables building and running valgrind targets during precommit.
Build is supposed to be turned on by an option that should be introduced later.
Valgrind-checked runs are supposed to be performed in asynchronous mode.
Peter Gal