[4.1] eeb2368 Avoid repeated copying of generated RST files.

[Lasse Karstensen]

commit eeb2368fb37583e3e75eaf46349f1d2855c4839e
Author: Lasse Karstensen <lkarsten at varnish-software.com>
Date:   Mon Dec 21 15:09:00 2015 +0100

    Avoid repeated copying of generated RST files.

diff --git a/doc/sphinx/Makefile.am b/doc/sphinx/Makefile.am
index e47a60d..52fa8de 100644
--- a/doc/sphinx/Makefile.am
+++ b/doc/sphinx/Makefile.am
@@ -159,17 +159,12 @@ include/varnishhist_synopsis.rst: $(top_builddir)/bin/varnishhist/varnishhist_op
 BUILT_SOURCES += include/varnishhist_options.rst \
 	 include/varnishhist_synopsis.rst
 
-.PHONY: reference
-reference:
-	test -d $@ || mkdir $@
-BUILT_SOURCES += reference
-
-reference/vmod_std.generated.rst: reference $(top_builddir)/lib/libvmod_std/vmod_std.rst
-	cp $(top_builddir)/lib/libvmod_std/vmod_std.rst $@
+reference/vmod_std.generated.rst: $(top_builddir)/lib/libvmod_std/vmod_std.rst
+	mkdir -p reference && cp $(top_builddir)/lib/libvmod_std/vmod_std.rst $@
 BUILT_SOURCES += reference/vmod_std.generated.rst
 
-reference/vmod_directors.generated.rst: reference $(top_builddir)/lib/libvmod_directors/vmod_directors.rst
-	cp $(top_builddir)/lib/libvmod_directors/vmod_directors.rst $@
+reference/vmod_directors.generated.rst: $(top_builddir)/lib/libvmod_directors/vmod_directors.rst
+	mkdir -p reference && cp $(top_builddir)/lib/libvmod_directors/vmod_directors.rst $@
 BUILT_SOURCES += reference/vmod_directors.generated.rst
 
 EXTRA_DIST += $(BUILT_SOURCES)