* guix/build/emacs-build-system.scm (move-doc): Adjust to use "/share/info" instead of its sub-directory.
* guix/build/emacs-build-system.scm (emacs-inputs): Fix matching pattern. (patch-el-files): Improve regexp pattern.
* Makefile.am (MODULES): Add 'guix/build-system/emacs.scm' and 'guix/build/emacs-build-system.scm'. * guix/build-system/emacs.scm: New file. * guix/build/emacs-build-system.scm: New file. * doc/guix.texi (Build Systems): Document it.