Install libnx-x11-dev by entering the following commands in the terminal:
sudo apt update sudo apt install libnx-x11-dev
nxagent's libNX_X11 client-part library (development headers)
NX is a software suite which implements very efficient compression of the X11 protocol. This increases performance when using X applications over a network, especially a slow one. . This package provides development headers of the libNX_X11 library (a libX11 drop-in replacement used by nxagent).