You have to install several X11 include files
or, better, install a complete X11R5 release. Hewlett-Packard doesn't
support the Athena Widgets. So the header files and libraries are missing
from the application media, but they are available as a patch.
They also do not ship the ANSI compiler with the normal operating
system release so you have to buy one or use GCC.
Some of the tools are available as patches.
In addition, Pcb has been successfully tested on these platforms with
HPUX 9.*, 10.* running self-compiled X11R5.