How to edit a djvu file in Wary Puppy 5.3?
 

It seems Wary Puppy 5.3 hasn't a djvu viewer application.
Is there something I can do?

There's a viewer in the fatdog repository:
http://puppylinux.org/wikka/DjVU

You can install things yourself, of course:
http://djvureader.com/djvu-linux.html
http://sourceforge.net/projects/djvu/

This gives you some background:
https://en.wikisource.org/wiki/Help:DjVu_files

It seems I'm on a right way. :D
I downloaded and saved djvulibre(tar.gz file),
then I tried to install it.
So I changed directory and tried to type ./configure,
make and make install. However there's an error: when I type
./configure it cannot find
a c compiler. How to solve it?

up!

Oops! I just assumed that Puppy would have one installed. Just to be sure, try whereis gcc. If you don't get an answer, you need to install gcc in Puppy: that should be in the repository. When you start wandering off the beaten track, these things happen.