First examine configure.h and change any of the defaults that you need
to.  Now, if you have Imake installed on your system, just run
"xmkmf;make Makefiles" (or ./MakeMakefiles) to build all of the
makefiles, then run make.  You'll need an ANSI C compiler to do this,
by the way (i.e. don't use cc under SunOS).

Then you can run 'make install' and 'make install.man' to install it
where you specified, but it doesn't have to be officially installed to
run it.

If you don't have Imake installed, then you'll probably have to hand
edit the existing makefiles (probably set up for AIX) or get the
makefiles that someone else used for your platform.

Note: plans are in the works to switch to GNU Autoconf scripts to
configure the makefiles which should make it even more portable and
easy to build.

Also, the FvwmConfig module currently doesn't build automatically,
since it's written in C++ and Imake doesn't support C++.  There is
a makefile in that directory that you can hand edit and hand build
the module for your system, if desired.
