[PATCH] doc/publican/Makefile.am: Add a missing order-only prerequisite

[Rui Matos]

Otherwise a parallel make invocation could fail due to the directory
not existing.

Signed-off-by: Rui Matos <tiagomatos at gmail.com>
---
 doc/publican/Makefile.am | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/doc/publican/Makefile.am b/doc/publican/Makefile.am
index 278da12..50a6188 100644
--- a/doc/publican/Makefile.am
+++ b/doc/publican/Makefile.am
@@ -85,7 +85,7 @@ $(builddir)/en-US/ProtocolSpec.xml: $(top_srcdir)/protocol/wayland.xml $(srcdir)
 	$(AM_V_GEN)$(XSLTPROC) $(srcdir)/protocol-to-docbook.xsl \
 		$(top_srcdir)/protocol/wayland.xml > $@
 
-$(builddir)/en-US/ProtocolInterfaces.xml: $(top_srcdir)/protocol/wayland.xml $(srcdir)/protocol-interfaces-to-docbook.xsl
+$(builddir)/en-US/ProtocolInterfaces.xml: $(top_srcdir)/protocol/wayland.xml $(srcdir)/protocol-interfaces-to-docbook.xsl | $(builddir)/en-US
 	$(AM_V_GEN)$(XSLTPROC) $(srcdir)/protocol-interfaces-to-docbook.xsl \
 		$(top_srcdir)/protocol/wayland.xml > $@
 
-- 
2.1.0