Fix build without Lout.

Reported by rvclayton@verizon.net (R. Clayton).

* doc/user/Makefile.am (BUILT_SOURCES): Leave empty when !HAVE_LOUT.
  (skrflags): Add `-e "(define %have-lout? ...)".

* doc/user/loute.skb (Additional Markup): Don't evaluate
  `src/lout-illustration.skb' when not %HAVE-LOUT?.
* doc/user/eq.skb (Equation Formatting): Use 'lout as the renderer only
  when %HAVE-LOUT?.
* doc/user/src/eq3.skb: Likewise.

4 files changed, 24 insertions, 8 deletions

diff --git a/doc/user/Makefile.am b/doc/user/Makefile.am
index b2920a5..3c07297 100644
--- a/doc/user/Makefile.am
+++ b/doc/user/Makefile.am
@@ -34,7 +34,13 @@ skrinfo_DATA = skribilo.info
 html_DATA = user.html user.sui
 dist_html_DATA = skribilo.css			\
   lobster-1.4.otf junction.ttf
+
+if HAVE_LOUT
 BUILT_SOURCES = lout/front-page.lout
+else !HAVE_LOUT
+BUILT_SOURCES =
+endif !HAVE_LOUT
+
 CLEANFILES = $(BUILT_SOURCES) $(html_DATA) skribilo.info
 
 # `user.sui' is produced by the HTML engine.
@@ -55,6 +61,11 @@ skrflags += -e "(define %have-ploticus? (= 0 1))"	\
 	    -e "(define %ploticus-path (= 0 1))"
 endif
 
+if HAVE_LOUT
+skrflags += -e "(define %have-lout? (= 1 1))"
+else
+skrflags += -e "(define %have-lout? (= 0 1))"
+endif
 
 load_path = $(top_srcdir)/doc/modules
 load_compiled_path = $(top_builddir)/doc/modules
diff --git a/doc/user/eq.skb b/doc/user/eq.skb
index ed11f66..91faf11 100644
--- a/doc/user/eq.skb
+++ b/doc/user/eq.skb
@@ -1,7 +1,7 @@
 ;;; eq.skb  --  Equation formatting.
 ;;; -*- coding: iso-8859-1 -*-
 ;;;
-;;; Copyright 2006, 2007, 2008, 2009  Ludovic Courtès <ludo@gnu.org>
+;;; Copyright 2006, 2007, 2008, 2009, 2012  Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;;
 ;;; This file is part of Skribilo.
@@ -32,7 +32,10 @@ may be loaded by adding the following form at the top of your document:]
       [It allows the inclusion of (complex) equations in your documents,
 such as, for example, the following:]
 	
-	(disp (eq :renderer (if (engine-format? "html") 'lout #f)
+	(disp (eq :renderer (if (and %have-lout?
+	                             (engine-format? "html"))
+	                        'lout
+				 #f)
                   :ident "eq-disponibilite"
 		  `(= (apply A D)
 		      (sum :from (= i b) :to (* S b)
diff --git a/doc/user/loute.skb b/doc/user/loute.skb
index ecfef34..4f0b27f 100644
--- a/doc/user/loute.skb
+++ b/doc/user/loute.skb
@@ -227,10 +227,12 @@ is ,(tt [#f]).]))
 When using other engines, it is integrated using ,(markup-ref
 "image").])
       
-      (example-produce
-        (example :legend "A Lout illustration"
-          (prgm :file "src/lout-illustration.skb"))
-        (disp (include "src/lout-illustration.skb")))))
+      (let ((e (example :legend "A Lout illustration"
+                 (prgm :file "src/lout-illustration.skb"))))
+        (if %have-lout?
+	    (example-produce e
+	      (disp (include "src/lout-illustration.skb")))
+	    e))))
 
 ;;; Local Variables:
 ;;; ispell-local-dictionary: "american"
diff --git a/doc/user/src/eq3.skb b/doc/user/src/eq3.skb
index e229b6c..50f5104 100644
--- a/doc/user/src/eq3.skb
+++ b/doc/user/src/eq3.skb
@@ -9,7 +9,7 @@ accordingly.])
 aligned with one another.])
 
    (eq :ident "eq-limit-b-over-l"
-       :renderer 'lout
+       :renderer (and %have-lout? 'lout)
        :align-with '=
        '(= (limit (/ lambda beta) 0
 		  (apply IPL n k))
@@ -26,7 +26,7 @@ aligned with one another.])
    [This equation can be simplified as follows:]
 
    (eq :ident "eq-limit-b-over-l-simplified"
-       :renderer 'lout
+       :renderer (and %have-lout? 'lout)
        :align-with '=
        '(= ;; simplified
 	   (/ (expt (+ alpha beta) k)