build manuals moved here from osmo-gsm-manuals.git

Moved to doc/manuals/, with full commit history, in preceding merge commit.
Now incorporate in the build system.

Build with:

$ autoreconf -fi
$ ./configure --enable-manuals
$ make

Shared files from osmo-gsm-manuals.git are found automatically if
- the repository is checked out in ../osmo-gsm-manuals; or
- if it osmo-gsm-manuals was installed with "make install"; or
- OSMO_GSM_MANUALS_DIR is set.

Related: OS#3385
Change-Id: I2762171af0bf719a34ba12a0c2e4dcc206098beb

configure.ac

@@ -223,6 +223,48 @@ PKG_CHECK_MODULES(FFTWF, fftw3f)
 AC_CHECK_HEADER([boost/config.hpp],[],
     [AC_MSG_ERROR([boost/config.hpp not found, install e.g. libboost-dev])])
 
+# Generate manuals
+AC_ARG_ENABLE(manuals,
+	[AS_HELP_STRING(
+		[--enable-manuals],
+		[Generate manual PDFs [default=no]],
+	)],
+	[osmo_ac_build_manuals=$enableval], [osmo_ac_build_manuals="no"])
+AM_CONDITIONAL([BUILD_MANUALS], [test x"$osmo_ac_build_manuals" = x"yes"])
+AC_ARG_VAR(OSMO_GSM_MANUALS_DIR, [path to common osmo-gsm-manuals files, overriding pkg-config and "../osmo-gsm-manuals"
+	fallback])
+if test x"$osmo_ac_build_manuals" = x"yes"
+then
+	# Find OSMO_GSM_MANUALS_DIR (env, pkg-conf, fallback)
+	if test -n "$OSMO_GSM_MANUALS_DIR"; then
+		echo "checking for OSMO_GSM_MANUALS_DIR... $OSMO_GSM_MANUALS_DIR (from env)"
+	else
+		OSMO_GSM_MANUALS_DIR="$($PKG_CONFIG osmo-gsm-manuals --variable=osmogsmmanualsdir 2>/dev/null)"
+		if test -n "$OSMO_GSM_MANUALS_DIR"; then
+			echo "checking for OSMO_GSM_MANUALS_DIR... $OSMO_GSM_MANUALS_DIR (from pkg-conf)"
+		else
+			OSMO_GSM_MANUALS_DIR="../osmo-gsm-manuals"
+			echo "checking for OSMO_GSM_MANUALS_DIR... $OSMO_GSM_MANUALS_DIR (fallback)"
+		fi
+	fi
+	if ! test -d "$OSMO_GSM_MANUALS_DIR"; then
+		AC_MSG_ERROR("OSMO_GSM_MANUALS_DIR does not exist! Install osmo-gsm-manuals or set OSMO_GSM_MANUALS_DIR.")
+	fi
+
+	# Find and run check-depends
+	CHECK_DEPENDS="$OSMO_GSM_MANUALS_DIR/check-depends.sh"
+	if ! test -x "$CHECK_DEPENDS"; then
+		CHECK_DEPENDS="osmo-gsm-manuals-check-depends"
+	fi
+	if ! $CHECK_DEPENDS; then
+		AC_MSG_ERROR("missing dependencies for --enable-manuals")
+	fi
+
+	# Put in Makefile with absolute path
+	OSMO_GSM_MANUALS_DIR="$(realpath "$OSMO_GSM_MANUALS_DIR")"
+	AC_SUBST([OSMO_GSM_MANUALS_DIR])
+fi
+
     # https://www.freedesktop.org/software/systemd/man/daemon.html
     AC_ARG_WITH([systemdsystemunitdir],
          [AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd service files])],,
@@ -267,4 +309,5 @@ AC_CONFIG_FILES([\
     contrib/systemd/Makefile \
 ])
 
-AC_OUTPUT
+AC_OUTPUT(
+	doc/manuals/Makefile)