doc: Make sure out-of-source-tree builds find os-config.tmpl.

* Makefile.am (BUILT_SOURCES): New variable.
* daemon.am (BUILT_SOURCES): Use +=.
* doc.am (BUILT_SOURCES, MAINTAINERCLEANFILES, EXTRA_DIST): Add
  doc/os-config.texi.
  (doc/os-config.texi): New target.
* doc/guix.texi (System Installation): Include os-config.texi.

Makefile.am

@@ -253,6 +253,7 @@ guix_install_go_files = install-nobase_nodist_guilemoduleDATA
 $(guix_install_go_files): install-nobase_dist_guilemoduleDATA
 
 SUBDIRS = po/guix po/packages
+BUILT_SOURCES =
 
 include doc.am
 

daemon.am

@@ -20,7 +20,7 @@
 # Integration of the `guix-daemon' code taken from upstream Nix.
 #
 
-BUILT_SOURCES = nix/libstore/schema.sql.hh
+BUILT_SOURCES += nix/libstore/schema.sql.hh
 CLEANFILES += $(BUILT_SOURCES)
 
 noinst_LIBRARIES = libformat.a libutil.a libstore.a

doc.am

@@ -1,5 +1,5 @@
 # GNU Guix --- Functional package management for GNU
-# Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
+# Copyright © 2012, 2013, 2014 Ludovic Courtès <ludo@gnu.org>
 # Copyright © 2013 Andreas Enge <andreas@enge.fr>
 #
 # This file is part of GNU Guix.
@@ -24,6 +24,15 @@ EXTRA_DIST +=					\
   doc/images/bootstrap-graph.eps		\
   doc/images/bootstrap-graph.pdf
 
+# Bundle this file so that makeinfo finds it in out-of-source-tree builds.
+BUILT_SOURCES        += doc/os-config.texi
+EXTRA_DIST           += doc/os-config.texi
+MAINTAINERCLEANFILES  = doc/os-config.texi
+
+doc/os-config.texi: gnu/system/os-config.tmpl
+	$(MKDIR_P) "`dirname "$@"`"
+	cp "$<" "$@"
+
 infoimagedir = $(infodir)/images
 dist_infoimage_DATA = doc/images/bootstrap-graph.png
 

doc/guix.texi

@@ -2856,7 +2856,7 @@ only a root account would look like this (on the installation system,
 this example is available as @file{/etc/configuration-template.scm}):
 
 @example
-@include gnu/system/os-config.tmpl
+@include os-config.texi
 @end example
 
 @noindent