src: watch ofono service for new modem

If system is using ofono, use ofono dbus service to figure out the
modem's USB id.

src/libgdbofono/meson.build

@@ -0,0 +1,50 @@
+#
+# Copyright (C) 2018 Purism SPC
+#
+# This file is part of Calls.
+#
+# Calls is free software: you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Calls is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Calls.  If not, see <http://www.gnu.org/licenses/>.
+#
+# Author: Bob Ham <bob.ham@puri.sm>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
+
+gnome = import('gnome')
+dbus_interfaces = ['manager', 'modem']
+
+gdbofono_src = []
+gdbofono_headers = []
+foreach iface: dbus_interfaces
+  src = gnome.gdbus_codegen(
+    'gdbo-' + iface,
+    iface + '.xml',
+    interface_prefix: 'org.ofono.',
+    namespace: 'GDBO'
+  )
+  gdbofono_src += src
+  gdbofono_headers += src[1]
+endforeach
+
+gdbofono_deps = [
+  dependency('gio-2.0'),
+  dependency('gio-unix-2.0'),
+]
+
+gdbofono_lib = static_library(
+  'gdbofono',
+  gdbofono_src,
+  dependencies: gdbofono_deps
+)