doc: Update metacpan.org API endpoint.

* doc/guix.texi (Invoking guix import): Match the URI actually used by the
updater.

gnu, doc, tests: Use ‘bootloader-configuration’ everywhere.

* doc/guix.texi (Proceeding with the Installation): Replace the old-style
‘grub-configuration’ with the newer ‘bootloader-configuration’ syntax.
* gnu/system/examples/vm-image.tmpl: Likewise.
* gnu/system/install.scm (installation-os): Likewise.
* gnu/tests.scm (%simple-os): Likewise.
* gnu/tests/install.scm (%minimal-os, %minimal-os-on-vda, %separate-home-os)
(%separate-store-os, %raid-root-os, %encrypted-root-os, %btrfs-root-os):
Likewise.
* gnu/tests/nfs.scm (%base-os): Likewise.
* tests/guix-system.scm (OS_BASE, make_user_config): Likewise.
* tests/system.scm (%os, %os-with-mapped-device): Likewise.

doc: Mention berlin.guixsd.org.

* doc/guix.texi (Substitute Server Authorization): Add note about
berlin.guixsd.org.  Nitpick.

maint: Add the '.iso' extension to installation images.

* Makefile.am (release): Add the '.iso' suffix to image files.
* doc/guix.texi (USB Stick and DVD Installation): Adjust accordingly.

doc: Merge "USB Stick Installation" and "DVD Installation".

* doc/guix.texi (USB Stick Installation): Rename to...
(USB Stick and DVD Installation): ... this.  Merge contents with...
(DVD Installation): ... this node.  Remove.

doc: Link to work on bootstrapping.

* doc/guix.texi (Reducing the Set of Bootstrap Binaries): New section.

doc: Update the example VCS snapshot package definition.

In commit ee17a9e06e636400e3354796a42ac445dbcc8f96, the helpers git-version
and git-file-name removed the need to build version and file name strings
manually for packages that use VCS snapshots.

doc/guix.texi (Version Numbers): Use git-version and git-file-name.

build-system: Add scons-build-system.

* guix/build-system/scons.scm: New file.
* guix/build/scons-build-system.scm: New file.
* Makefile.am (MODULES): Register them.
* doc/guix.texi (Build Systems): Add scons-build-system.

doc: Give the absolute file name of 'hydra.gnu.org.pub' in snippets.

* doc/guix.texi (Substitute Server Authorization): Give the absolute
file name of 'hydra.gnu.org.pub' in the snippet.

gexp: 'compiled-modules' disables deprecation warnings by default.

This avoids repeated deprecation messages, particularly while running
'guix system build' or similar.

* guix/gexp.scm (gexp->derivation): Add #:deprecation-warnings.  Pass it
to 'compiled-modules'.
(compiled-modules): Add #:deprecation-warnings and honor it.
* doc/guix.texi (G-Expressions): Update 'gexp->derivation'
documentation.
* guix/packages.scm (patch-and-repack): Pass #:deprecation-warnings #t.

services: Add Git HTTP(S) service support.

* doc/guix.texi (Version Control Services): Add documentation on the HTTP
backend for git.
* gnu/services/version-control.scm (<git-http-configuration>): New data type.
(git-http-nginx-location-configuration): New helper function.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

doc: Create "Version Control Services" section.

* doc/guix.texi (Version Control Services): Move to its own node.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

services: Add certbot service.

* gnu/services/certbot.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add new file.
* doc/guix.texi (Certificate Services): New section.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

services: xorg: Remove WindowMaker as a default fallback.

* gnu/services/xorg.scm (xinitrc)[builder](system-profile)
(user-profile): New variables.
(xsession-command, find-session): New procedures.
When FALLBACK-SESSION is #f, find a valid session at run time.
* doc/guix.texi (X Window): Adjust accordingly, and insist that one
or more window managers must be installed.

services: xorg: Document 'slim-configuration' and deprecate 'slim-service'.

* gnu/services/xorg.scm (<slim-configuration>): Provide default values
for all fields.
(slim-service-type)[default-value]: New field.
* doc/guix.texi (X Window): Remove 'slim-service' documentation.
Document 'slim-service-type' and 'slim-configuration'.
* gnu/services/desktop.scm (%desktop-services): Use 'slim-service-type'.

services: xorg: Allow users to specify a list of modules.

* gnu/services/xorg.scm (%default-xorg-fonts): New variable.
(xorg-configuration-file): Add #:modules and #:fonts.  Rewrite to return
a 'computed-file' that honors MODULES and FONTS.
(xorg-wrapper): Pass #:modules to 'xorg-configuration-file'.
(xorg-start-command): Add #:fonts.  Pass #:fonts and #:modules to
'xorg-configuration-file'.
* doc/guix.texi (X Window): Adjust documentation of 'xorg-start-command'
and 'xorg-configuration-file'.

services: configuration: Show default values of list types.

* doc/guix.texi (Messaging Services): Regenerate it.
* gnu/services/configuration.scm (show-default?): Check VAL rather than DEFAULT.
* gnu/services/messaging.scm (show-default?): Check VAL rather than DEFAULT.
(prosody-configuration)[modules-enabled]: Remove default value from docstring.

services: prosody: Add support for disable-sasl-mechanisms.

* doc/guix.texi (Messaging Services): Update accordingly.
* gnu/services/messaging.scm (prosody-configuration)[disable-sasl-mechanisms]:
New field.

services: prosody: Allow to add raw content to the config file.

* doc/guix.texi (Messaging Services): Update accordingly.
* gnu/services/messaging.scm (prosody-configuration)[raw-content]: New field.
(raw-content?, serialize-raw-content): New procedures.

services: prosody: Add support for http-max-content-size.

* doc/guix.texi (Messaging Services): Update accordingly.
* gnu/services/messaging.scm (prosody-configuration)[http-max-content-size]:
New field.