build: Add soup2 option

!1940 added support for soup 3, including a fallback to soup 2.4
where the newer version isn't available.

Unfortunately it missed that libgweather has a hidden soup dependency,
and now gnome-shell fails to start if a weather location has been set
up and soup 3 is available.

We don't have a good way to detect that case, so hide the soup 3 support
behind a build option. Distributors are expected to switch it at the
same time as libgweather.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1966>

js/misc/config.js.in

@@ -8,6 +8,8 @@ var PACKAGE_VERSION = '@PACKAGE_VERSION@';
 var HAVE_BLUETOOTH = @HAVE_BLUETOOTH@;
 /* 1 if networkmanager is available, 0 otherwise */
 var HAVE_NETWORKMANAGER = @HAVE_NETWORKMANAGER@;
+/* 1 if soup3 support is enabled, 0 otherwise */
+var HAVE_SOUP2 = @HAVE_SOUP2@;
 /* gettext package */
 var GETTEXT_PACKAGE = '@GETTEXT_PACKAGE@';
 /* locale dir */

js/misc/meson.build

@@ -5,6 +5,7 @@ jsconf.set('GETTEXT_PACKAGE', meson.project_name())
 jsconf.set('LIBMUTTER_API_VERSION', mutter_api_version)
 jsconf.set10('HAVE_BLUETOOTH', bt_dep.found())
 jsconf.set10('HAVE_NETWORKMANAGER', have_networkmanager)
+jsconf.set10('HAVE_SOUP2', have_soup2)
 jsconf.set('datadir', datadir)
 jsconf.set('libexecdir', libexecdir)
 

js/ui/environment.js

@@ -12,6 +12,8 @@ imports.gi.versions.TelepathyGLib = '0.12';
 imports.gi.versions.TelepathyLogger = '0.2';
 
 try {
+    if (Config.HAVE_SOUP2)
+        throw new Error('Soup3 support not enabled');
     const Soup_ = imports.gi.Soup;
 } catch (e) {
     imports.gi.versions.Soup = '2.4';