doc: make target for pdf, and suricata.1 shortcut

doc/userguide/Makefile.am

@@ -26,19 +26,30 @@ EXTRA_DIST = \
 if HAVE_SPHINXBUILD
 man1_MANS = _build/man/suricata.1
 
+SPHINX_BUILD = sphinx-build -q
+
 html:
 	sysconfdir=$(sysconfdir) \
 	localstatedir=$(localstatedir) \
 	version=$(PACKAGE_VERSION) \
-		sphinx-build -b html -d _build/doctrees \
+		$(SPHINX_BUILD) -b html -d _build/doctrees \
 		$(top_srcdir)/doc/userguide _build/html
 
+pdf:
+	sysconfdir=$(sysconfdir) \
+	localstatedir=$(localstatedir) \
+	version=$(PACKAGE_VERSION) \
+		$(SPHINX_BUILD) -b latex -d _build/doctrees \
+		$(top_srcdir)/doc/userguide _build/latex
+	cd _build/latex && $(MAKE) all-pdf
+
 _build/man/suricata.1:
 	sysconfdir=$(sysconfdir) \
 	localstatedir=$(localstatedir) \
 	version=$(PACKAGE_VERSION) \
-		sphinx-build -b man -d _build/doctrees \
+		$(SPHINX_BUILD) -b man -d _build/doctrees \
 		$(top_srcdir)/doc/userguide _build/man
+man: _build/man/suricata.1
 
 clean-local:
 	rm -rf $(top_builddir)/doc/userguide/_build