You need to add this line back in.  Without it, I get linker errors on Linux:

```
/usr/bin/ld: CMakeFiles/test-vrt.dir/lib/queue.c.o: undefined reference to symbol 'pthread_create@@GLIBC_2.2.5'
/usr/bin/ld: note: 'pthread_create@@GLIBC_2.2.5' is defined in DSO /usr/lib/libpthread.so.0 so try adding it to the linker command line
```