Wait the debug thread has terminated before freeing PLC to avoid random segmentation fault.

Store working directory to globals copy, in order to be used in runtime.py.

<?xml version="1.0" encoding="UTF-8"?>
<BeremizRoot URI_location="LOCAL://">
  <TargetType>
    <Linux CFLAGS="-g" LDFLAGS=""/>
  </TargetType>
</BeremizRoot>