From 0874edfdf817ec3126b40cbae8541e4377cee9bb Mon Sep 17 00:00:00 2001
From: Jaap Versteegh <j.r.versteegh@gmail.com>
Date: Wed, 13 Dec 2017 13:05:45 +0100
Subject: [PATCH] Fixed issue with HAVE_DOXYGEN define

---
 configure.ac    |  4 ++++
 doc/Makefile.am | 27 ++++++++++++++++++---------
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/configure.ac b/configure.ac
index 76e3373..d32d991 100755
--- a/configure.ac
+++ b/configure.ac
@@ -435,6 +435,10 @@ char	string[16];
 ]
 )
 
+AC_PATH_PROG([DOXYGEN], [doxygen], [])
+AM_CONDITIONAL([HAVE_DOXYGEN], [test -n "$DOXYGEN"])
+AM_COND_IF([HAVE_DOXYGEN], AC_CONFIG_FILES([doc/Doxyfile]))
+
 #AC_CONFIG_FILES([Makefile])
 AC_OUTPUT(Makefile bin/Makefile man/Makefile)
 
diff --git a/doc/Makefile.am b/doc/Makefile.am
index f66174c..c4f9a50 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -1,15 +1,24 @@
-#if HAVE_DOXYGEN
-
 directory = $(top_srcdir)/doc
 
-$(directory)/html: Doxyfile
-	$(DOXYGEN) Doxyfile
+if HAVE_DOXYGEN
 
-all-local: $(directory)/html
+doxygen-build.stamp: Doxyfile
+	$(DOXYGEN) Doxyfile
+	touch $@
+
+else
+
+doxygen-build.stamp:
+	@echo "*** Doxygen not found. Documentation will not be build."
+	touch $@
+
+endif
+
+all-local: doxygen-build.stamp
 
 clean-local:
-	rm -rf $(directory)/html
-	rm -rf $(directory)/man
-	rm -rf $(directory)/xml
+	rm -f doxygen-build.stamp
+	rm -rf html
+	rm -rf man
+	rm -rf xml
 
-#endif