manuals: generate vty reference xml at build time

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

Remove msc_vty_reference.xml 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-msc --vty-ref-xml cmdline switch.

Depends: I613d692328050a036d05b49a436ab495fc2087ba (osmo-gsm-manuals)
Change-Id: Ib872e7979c5b5a9da1347a3f326307844cf76536

Makefile.am

@@ -9,9 +9,9 @@ AM_CPPFLAGS = \
 	$(NULL)
 
 SUBDIRS = \
-	doc \
 	include \
 	src \
+	doc \
 	contrib \
 	tests \
 	$(NULL)

doc/manuals/Makefile.am

@@ -14,6 +14,11 @@ if BUILD_MANUALS
   VTY_REFERENCE = osmomsc-vty-reference.xml
   include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.vty-reference.inc
 
+  BUILT_REFERENCE_XML = $(builddir)/vty/msc_vty_reference.xml
+  $(builddir)/vty/msc_vty_reference.xml: $(top_builddir)/src/osmo-msc/osmo-msc
+	mkdir -p $(builddir)/vty
+	$(top_builddir)/src/osmo-msc/osmo-msc --vty-ref-xml > $@
+
   OSMO_REPOSITORY = osmo-msc
   include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.common.inc
 endif