getting started with guile dev

[Tobin Harding]

I am attempting to get started on some guile hacks. I am running Emacs, Geiser,
Guile (2.0.11) for Scheme development.

I have cloned the git repository for Guile (current commit d545e45). I can 
configure
and build this tree. I can run the executable

$ GUILE_TREE/libguile/guile --version
guile (GNU Guile) 2.1.3.11-d545e-dirty
Copyright (C) 2016 Free Software Foundation, Inc.

My question is this, please, how to replace the system version with the fresh
build.

make install does not achieve this.

Also I tried running
$ GUILE_TREE/libguile/guile -L $GUILE_TREE/modules/

but that does not seem to load the new modules.

thanks,
Tobin Harding.