[tracker] build: Require dia when building documentation

[Martyn James Russell <mr src gnome org>]

commit 2d97f138a96da1e341850fa5ff2aae03437a343b
Author: Martyn Russell <martyn lanedo com>
Date:   Fri Dec 10 10:07:53 2010 +0000

    build: Require dia when building documentation
    
    Fixes GB#636936

 configure.ac                        |    8 ++++++++
 docs/reference/ontology/Makefile.am |    2 +-
 2 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 7a99e10..84dda06 100644
--- a/configure.ac
+++ b/configure.ac
@@ -575,6 +575,14 @@ GTK_DOC_CHECK([1.8])
 if test "x$enable_gtk_doc" != "xno"; then
    AC_DEFINE(HAVE_GTK_DOC, 1, [Define if we have gtk-doc (with gtk-doc)])
 
+   # Check for dia if we are building gtk_doc
+   AC_PATH_PROG(DIA, dia)
+   AC_SUBST(DIA)
+
+   if test -z "$DIA"; then
+      AC_MSG_ERROR([Could not find Dia tool required to build documentation.])
+   fi
+
    # Check for graphviz if we are building gtk_doc
    AC_PATH_PROG(GRAPHVIZ_FDP, fdp)
    AC_SUBST(GRAPHVIZ_FDP)
diff --git a/docs/reference/ontology/Makefile.am b/docs/reference/ontology/Makefile.am
index cf2a096..db4bb10 100644
--- a/docs/reference/ontology/Makefile.am
+++ b/docs/reference/ontology/Makefile.am
@@ -27,7 +27,7 @@ ONTOLOGY_DIAGRAMS_PNG = $(notdir $(ONTOLOGY_DIAGRAMS:.dia=.png))
 
 # DIA to PNG conversion
 $(ONTOLOGY_DIAGRAMS_PNG): $(ONTOLOGY_DIAGRAMS)
-	dia -t png $^ 2>/dev/null
+	$(AM_V_GEN) $(DIA) -t png $^ 2>/dev/null
 
 # The original Ontology explanation files
 ONTOLOGY_EXPLANATIONS =                                \