Sporadic build failures are visible on the build bots.
libyate.so: undefined reference to `TelEngine::ClientLogic::initStaticData()'
libyate.so: undefined reference to `TelEngine::DefaultLogic::DefaultLogic(char const*, int)'
collect2: error: ld returned 1 exit status
Turning off parallel builds should (hopefully) work around this.
Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>