Compilation error: undefined reference to symbol 'pthread_setname_np@@GLIBC_2.12'

Summary

The opensource build of the TITAN can't be compiled

Steps and/or TTCN-3 code to reproduce

make

What is the current bug behavior?

undefined reference to symbol 'pthread_setname_np@@GLIBC_2.12'

What is the expected correct behavior?

successfull compilation

Possible fixes

The -lpthread is missing from the LINUX_LIBS, add it to the line 80 of the core/Makefile

Titan version

from commit de0bf8b2

Platform details (OS type and version)

(OS type/distribution and version, e.g. Ubuntu 18.04, Windows 10+Cygwin)

/cc @aknappqwt @mmagyari