display-server> echo $DISPLAY
localhost:10.0
display-server> xhost + <code_compiling_server_name_or_ip_address>

code-compiling-server> export DISPLAY=display-server:10.0
code-compiling-server> /usr/X11R6/bin/xclock  # Test if it works.

display-server> xhost -   ## Do this after you are done compiling and testing ##