This follows a convention used by some other GNU packages like Autoconf,
Bison, Coreutils, and Gnulib.
* doc.am: Rename to ...
* doc/local.mk: ... this.
* emacs.am: Rename to ...
* emacs/local.mk: ... this.
* gnu-system.am: Rename to ...
* gnu/local.mk: ... this.
* daemon.am: Rename to ...
* nix/local.mk: ... this.
* Makefile.am: Adapt to them.
* doc/guix.texi (Porting to a New Platform): Adapt documentation.
* guix/config.scm.in (%state-directory, %config-directory): Adapt comments.
* emacs/guix-config.el.in (guix-config-state-directory): Likewise.
This allows build outputs to be transparently downloaded from
http://hydra.gnu.org, for example.
* config-daemon.ac: Check for `gzip', `bzip2', and `xz'.
* guix/config.scm.in (%gzip, %bzip2, %xz): New variable.
* guix/scripts/substitute-binary.scm (fetch): Return SIZE as a second value.
(<narinfo>): Change `url' to `uri'.
(make-narinfo): Rename to...
(narinfo-maker): ... this. Handle relative URLs.
(fetch-narinfo): Adjust accordingly.
(filtered-port, decompressed-port): New procedures.
(guix-substitute-binary): Implement the `--substitute' case.
* tests/store.scm ("substitute query"): Use (%store-prefix) instead
of (getenv "NIX_STORE_DIR").
("substitute"): New test.
* configure.ac: Compute and substitute `guix_localstatedir'.
* m4/guix.m4: Substitute `guix_system'.
* guix/config.scm.in (%store-directory, %store-directory, %system): New
variables.
* guix/store.scm (%nix-state-dir): Remove.
(%default-socket-path): Use %STATE-DIRECTORY as the default.
(%store-prefix): Use %STORE-DIRECTORY as the default.
* guix/utils.scm (%current-system): Default to %SYSTEM.