Where are the Motif includes and libraries?

Starting with Solaris 2.4, the package SUNWmfrun is included with
the base OS. It is installed under the directory /usr/dt,
where all the CDE stuff is installed (dt stands for desktop).

There are no Motif imake templates nor is mwm shipped with the
base OS; only the mwm -like Dtwm is shipped.

Remember that you must link with -R/usr/dt/lib.