manuals/OsmoNITB: integrate into this repository

Move from doc/manuals to manuals/OsmoNITB as we have two more manuals
(OsmoMGCP and OsmoNAT) that need to be moved to manuals/. Make the
manuals build without a toplevel configure.ac file from autotools:

$ cd manuals/OsmoNITB
$ make

openbsc/configure.ac is not used to integrate the manuals, as it would
be extra effort to integrate all three of the manuals there. This is
not worth it for the legacy codebase.

Related: OS#3385
Change-Id: I0036ad8dbecd23695305ac491c7ee87caa44c7f9

manuals/.gitignore

@@ -0,0 +1,8 @@
+*.html
+*.svg
+*.pdf
+*__*.png
+*.check
+generated
+common
+build

manuals/OsmoNITB/Makefile

@@ -1,9 +1,5 @@
-OSMO_GSM_MANUALS_DIR = $(top_srcdir)
-EXTRA_DIST = osmonitb-usermanual.adoc \
-	osmonitb-usermanual-docinfo.xml \
-	osmonitb-vty-reference.xml \
-	chapters \
-	vty
+OSMO_GSM_MANUALS_DIR := $(shell ../osmo-gsm-manuals-dir.sh)
+srcdir=$(CURDIR)
 
 ASCIIDOC = osmonitb-usermanual.adoc
 ASCIIDOC_DEPS = $(srcdir)/chapters/*.adoc

manuals/osmo-gsm-manuals-dir.sh

@@ -0,0 +1,26 @@
+#!/bin/sh -e
+# Find OSMO_GSM_MANUALS_DIR and print it to stdout. Print where it was taken from to stderr.
+
+# Find it in env, pkg-conf and ../../osmo-gsm-manuals
+RET="$OSMO_GSM_MANUALS_DIR"
+if [ -n "$RET" ]; then
+	RET="$(realpath $RET)"
+	echo "OSMO_GSM_MANUALS_DIR: $RET (from env)" >&2
+else
+	RET="$(pkg-config osmo-gsm-manuals --variable=osmogsmmanualsdir 2>/dev/null || true)"
+	if [ -n "$RET" ]; then
+		echo "OSMO_GSM_MANUALS_DIR: $RET (from pkg-conf)" >&2
+	else
+		RET="$(realpath $(realpath $(dirname $0))/../../osmo-gsm-manuals)"
+		echo "OSMO_GSM_MANUALS_DIR: $RET (fallback)" >&2
+	fi
+fi
+
+# Print the result or error message
+if [ -d "$RET" ]; then
+	echo "$RET"
+else
+	echo "ERROR: OSMO_GSM_MANUALS_DIR does not exist!" >&2
+	echo "Install osmo-gsm-manuals or set OSMO_GSM_MANUALS_DIR." >&2
+	exit 1
+fi