Initial commit

Introduces the plugin, which itself depends on GStreamer,
GDBus, and GLib in general.

meson.build

+project('obs-xdg-portal', 'c')
+
+shared_library('obs-xdg-portal',
+  'obs-xdg-portal.c',
+  name_prefix : '',
+  dependencies : [
+    meson.get_compiler('c').find_library('obs'),
+    dependency('gio-2.0'),
+    dependency('gio-unix-2.0'),
+    dependency('gstreamer-1.0'),
+    dependency('gstreamer-app-1.0'),
+    dependency('gstreamer-video-1.0'),
+  ],
+  install : true,
+  install_dir : 'lib/obs-plugins'
+)