Check dtplite is really available

diff --git a/Makefile.in b/Makefile.in
index 194e30a95b2d0a452aa4202f777e7947914d7fe7..33246d7dcbbfb04a5491f47607f5b153cef1dc95 100644 (file)
--- a/Makefile.in
+++ b/Makefile.in
@@ -191,11 +191,14 @@ DTPLITE=@DTPLITE@
 doc: udp.n
 
 udp.n: $(srcdir)/doc/udp.man
-       test -x $(DTPLITE) && $(DTPLITE) -o $@ nroff $(srcdir)/doc/udp.man
+       @if [ -n "$(DTPLITE)" -a -x "$(DTPLITE)" ]; then \
+           $(DTPLITE) -o $@ nroff $(srcdir)/doc/udp.man ; \
+       fi
 
 udp.html: $(srcdir)/doc/udp.man
-       test -x $(DTPLITE) && $(DTPLITE) -o $@ html $(srcdir)/doc/udp.man
-
+       @if [ -n "$(DTPLITE)" -a -x "$(DTPLITE)" ]; then \
+           $(DTPLITE) -o $@ html $(srcdir)/doc/udp.man ; \
+       fi
 
 install: all install-binaries install-libraries install-doc