I have compiled Mosaic successfully on a NetBSD current snapshot from
last month. There was no need to use a canned makefile - the configure
scripts work fine if lesstif is installed (I pre-built and later
configured Mosaic with the jpeg, png, and z libs also, which is pretty
standard.) You will need to change the libpng makefile to use ranlib (if
you want to use png graphics), and then run the configure script in the
Mosaic-src directory with a command like;
./configure --with-jpegdir=/usr/local/lib/jpeg-6a/ 
            --with-pngdir=/usr/local 
            --with-zdir=/usr/local
During compile, you will encounter the infamous sys_errlist doubly
defined message, so just temporarily comment out that line in
/usr/include/errno.h. Later, you will have to edit some .h files and
move most of their comment to the corresponding .c files (I think the
comment forms in comment.h had to be moved to the top of comment.c and
then comment.o recompiled) to prevent the linker from spitting out
multiply defined segment errors. Finally, during the linking stage for
the Mosaic application, you will have to edit the makefile in the src
directory and tell it where some X libraries are -  tell the makefile to
include libICE, libXt, libX11, and some others while linking. Hope this
helps. If anybody wants, I could post step by step instructions on how
to build Mosaic, but then that kind of limits your installation and
compile options (Mosaic is full of them!)

-Steven Hascall
shascal@siue.edu