gnu: Introduce the (gnu services ...) modules.

* gnu/system/dmd.scm: Remove file.  Move contents to...
* gnu/services.scm, gnu/services/base.scm, gnu/services/dmd.scm,
  gnu/services/networking.scm, gnu/services/xorg.scm: ... here.  New
  files.
* gnu/system.scm, gnu/system/vm.scm: Adjust accordingly.
* guix/scripts/system.scm (%user-module): Likewise.
* doc/guix.texi (Using the Configuration System): Likewise.
  (Defining Services): Likewise.

1 files changed, 8 insertions, 3 deletions

diff --git a/gnu-system.am b/gnu-system.am
index d231cfa57b6..857c9bf6631 100644
--- a/gnu-system.am
+++ b/gnu-system.am
@@ -70,7 +70,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/packages/fonts.scm                        \
   gnu/packages/fontutils.scm                    \
   gnu/packages/freeipmi.scm                     \
-  gnu/packages/games.scm                        \
+  gnu/packages/games.scm                        \
   gnu/packages/gawk.scm                         \
   gnu/packages/gcal.scm                         \
   gnu/packages/gcc.scm                          \
@@ -210,7 +210,7 @@ GNU_SYSTEM_MODULES =				\
   gnu/packages/vpn.scm                          \
   gnu/packages/w3m.scm                          \
   gnu/packages/wdiff.scm                        \
-  gnu/packages/web.scm                          \
+  gnu/packages/web.scm                          \
   gnu/packages/wget.scm                         \
   gnu/packages/which.scm                        \
   gnu/packages/wordnet.scm                      \
@@ -223,8 +223,13 @@ GNU_SYSTEM_MODULES =				\
   gnu/packages/zile.scm                         \
   gnu/packages/zip.scm                          \
                                                 \
+  gnu/services.scm                              \
+  gnu/services/base.scm                         \
+  gnu/services/dmd.scm                          \
+  gnu/services/networking.scm                   \
+  gnu/services/xorg.scm                         \
+                                                \
   gnu/system.scm                                \
-  gnu/system/dmd.scm                            \
   gnu/system/grub.scm                           \
   gnu/system/linux.scm                          \
   gnu/system/linux-initrd.scm                   \