Target asterisk.pdf stopped building when the build was moved to the doc directory.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@77602 65c4cc65-6c06-0410-ace0-fbb531ad65f3

Makefile

@@ -700,6 +700,7 @@ menuselect-tree: $(foreach dir,$(filter-out main,$(MOD_SUBDIRS)),$(wildcard $(di
 	@echo "Generating input for menuselect ..."
 	@build_tools/prep_moduledeps > $@
 
-asterisk.pdf: doc/asterisk.pdf
+asterisk.pdf:
+	$(MAKE) -C doc/tex asterisk.pdf
 
 .PHONY: menuselect main sounds clean dist-clean distclean all prereqs cleantest uninstall _uninstall uninstall-all dont-optimize $(SUBDIRS_INSTALL) $(SUBDIRS_CLEAN) $(SUBDIRS_UNINSTALL) $(SUBDIRS) $(MOD_SUBDIRS_EMBED_LDSCRIPT) $(MOD_SUBDIRS_EMBED_LDFLAGS) $(MOD_SUBDIRS_EMBED_LIBS) menuselect.makeopts