Missing Yodl packages does not break build process

CHANGES

@@ -1,5 +1,4 @@
 
-<<<<<<< HEAD
 Corrections:
 	In error.c msg2() there was a stack overflow on long messages: The
 	terminating \0 Byte was written behind the last position.
@@ -77,6 +76,11 @@ Porting:
 	Solaris derivatives no longer need librt for clock_gettime()
 	Thanks to Andy Fiddaman to directing me to the patch.
 
+Building:
+	Failure during building documentation, e.g. due to missing Yodl
+	packages, now does not let the build process fail.
+	Feature requested by Seyhun.
+
 Features:
 	Filan prints target of symlink when appropriate
 	Test: FILANSYMLINK

Makefile.in

@@ -100,11 +100,11 @@ docclean:
 	rm -f doc/socat.1 doc/socat.html
 
 doc/socat.1: doc/socat.yo
-	mkdir -p $(@D); yodl2man -o $@ $+
+	-mkdir -p $(@D); yodl2man -o $@ $+
 
 doc/socat.html: doc/socat.yo
 # care for refs in html
-	mkdir -p $(@D); cd $(@D); yodl2html -o socat.html ../$+; cd ..
+	-mkdir -p $(@D); cd $(@D); yodl2html -o socat.html ../$+; cd ..
 
 progs: $(PROGS)