manuals: generate vty reference xml at build time

Move 'doc' subdir further down to "make sure" the osmo-bsc binary is built
before the docs

Rremove sgsn_vty_reference from the source tree.

In manuals//Makefile.am use the new BUILT_REFERENCE_XML feature recently added
to osmo-gsm-manuals, and add a build target to generate the XML using the new
osmo-sgsn --vty-ref-xml cmdline switch.

Change-Id: Ied75fdd13283aa592350994fb4febce06c213d3a
Depends: I613d692328050a036d05b49a436ab495fc2087ba

Makefile.am

@@ -9,11 +9,11 @@ AM_CPPFLAGS = \
 	$(NULL)
 
 SUBDIRS = \
-	doc \
 	include \
 	src \
 	contrib \
 	tests \
+	doc \
 	$(NULL)
 
 BUILT_SOURCES = $(top_srcdir)/.version

doc/manuals/Makefile.am

@@ -12,6 +12,12 @@ if BUILD_MANUALS
   include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.asciidoc.inc
 
   VTY_REFERENCE = osmosgsn-vty-reference.xml
+
+  BUILT_REFERENCE_XML = $(builddir)/vty/sgsn_vty_reference.xml
+  $(builddir)/vty/sgsn_vty_reference.xml: $(top_builddir)/src/sgsn/osmo-sgsn
+	mkdir -p $(builddir)/vty
+	$(top_builddir)/src/sgsn/osmo-sgsn --vty-ref-xml > $@
+
   include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.vty-reference.inc
 
   OSMO_REPOSITORY = osmo-sgsn