data: Use auto-generated but hardcoded autosuspend hwdb file

This solves various problems:
 1. It stays the same also if some drivers have been disabled
 2. It uses a stable path for being imported by systemd
 3. It is still checked for its validity by tests
 4. It can be auto-generated using a simple command

libfprint/fprint-list-udev-hwdb.c

@@ -168,8 +168,13 @@ int
 main (int argc, char **argv)
 {
   g_autoptr(GArray) drivers = fpi_get_driver_types ();
+  g_autofree char *program_name = NULL;
   guint i;
 
+  program_name = g_path_get_basename (argv[0]);
+  g_print ("# This file has been generated using %s with all drivers enabled\n",
+           program_name);
+
   printed = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
 
   for (i = 0; i < drivers->len; i++)

libfprint/meson.build

@@ -301,16 +301,24 @@ udev_hwdb = executable('fprint-list-udev-hwdb',
     link_with: libfprint_drivers,
     install: false)
 
-# We always build this file; primarily so that systemd can pull it
-# from the artefacts!
-custom_target('udev-rules',
-    output: '60-autosuspend-@0@.hwdb'.format(meson.project_name()),
+udev_hwdb_generator = custom_target('udev-hwdb',
+    output: 'autosuspend.hwdb',
+    depend_files: drivers_sources,
     capture: true,
     command: [ udev_hwdb ],
-    install: get_option('udev_rules'),
-    install_dir: udev_hwdb_dir,
-    build_by_default: true
-    )
+    install: false,
+)
+
+custom_target('sync-udev-hwdb',
+    depends: udev_hwdb_generator,
+    output: 'sync-udev-hwdb',
+    install: false,
+    command: [
+        'cp', '-v',
+        udev_hwdb_generator.full_path(),
+        meson.source_root() / 'data'
+    ]
+)
 
 supported_devices = executable('fprint-list-supported-devices',
     'fprint-list-supported-devices.c',