Hi.  I apologize for any mistakes and welcome feedback.  This is my
first patch to Guix; let's hope that many others will follow!  I see low
hanging fruits: including the several other Emacs packages still
unnecessarily pulling emacs-transient, emacs-project and other Elisp
libraries that are now builtin.

I have been using these modified packages.  I have also checked this
patch with ~guix lint~ and ~guix build --check~.  The four packages
build well; the only warning messages were:

In git-timemachine-completing-read-fn:
git-timemachine.el:101:8: Warning: docstring wider than 80 characters

In git-timemachine--find-new-current-line:
git-timemachine.el:259:8: Warning: docstring wider than 80 characters

In git-timemachine--get-cursor-position:
git-timemachine.el:294:8: Warning: docstring wider than 80 characters

In git-timemachine--set-cursor-position:
git-timemachine.el:300:8: Warning: docstring wider than 80 characters
git-timemachine.el:347:1: Warning: ‘define-transient-command’ is an obsolete
    alias (as of Transient 0.3.0); use ‘transient-define-prefix’ instead.

In end of data:
git-timemachine.el:247:19: Warning: the function ‘erm-reset-buffer’ is not
    known to be defined.

geiser-autodoc.el:69:12: Warning: ‘eldoc-message’ is an obsolete function (as
    of eldoc-1.1.0); use ‘eldoc-documentation-functions’ instead.

git-commit-pkg.el:1:2: Warning: the function ‘define-package’ is not known to
    be defined.