One caveat there: there's not enough quota underneath the dia
directory to hold the source and object files produced, so one has to
copy the sources (and helper scripts) to another location, like /tmp,
before compilation.

Dia has two main dependencies that need to be satisfied before it can
be compiled: libxml and gdk-pixbuf.  
the source for both is located here along with the source for dia.

[ Update [pnkfelix] Wed Jun 26 15:04:12 EDT 2002  
  dia-0.90 adds an additional dependency on libunicode, which I have
  added to the src directory.  Also, it requires a more recent version 
  of libxml than what the online documentation for Dia says; I have
  also added that to the src directory ]
 

The two have no interdependencies as far as I know, so they can be
compiled in tandem.  But "dia" cannot even be configured until they
are installed for a particular architecture.

the try-* scripts attempt to "do the right thing" in terms of setting
up environment variables, etc, before calling configure.  These are
hard-coded for working on athena; they're not useful to you if you've
copied the tar.gz's to a non-athena machine.

So, in short, run:

    try-gdk-pixbuf

Then at this point you need to take the program "test-gdk-pixbuf" out
of the list denoted by the variable 
"noinst_PROGRAMS = ... "
in the file: gdk-pixbuf/gdk-pixbuf/Makefile  

and finally:
    cd gdk-pixpuf; make; make install; cd -
    try-libxml
    cd libxml; make; make install; cd -
    try-dia
    cd dia; make; make install; cd -