ddd configure errors

[Edward A Hille]

I am trying to configure ddd-3.3 on an x386 machine running redhat Linux
7.0. I downloaded and successfully compiled lesstif-0.92.26, but when I
run configure in the ddd-3.3 directory, I get the following error message:

checking for XmCreateOptionMenu in -lXm... no
checking for xmUseVersion in -lXm... no
checking for XmInstallImage in -lXm... no
checking for Xm21InstallImage in -lXm... no
configure: error: The Motif library '-lXm' could not be found.
                  Please use the configure options
'--with-motif-includes=DIR'
                  and '--with-motif-libraries=DIR' to specify the Xm
location.
                  See the files 'config.log' and 'ddd/config.log'
                  for further diagnostics.
configure: error: ./configure failed for ddd



Do you have any suggestions as to what my next step should be?

Thank you for your help,

Ted Hille