gnome module: fix regression that broke using built xml files as gresources

In commit 3dcc712 we moved to
typed_pos_args. In the process, we deleted some code to specifically
raise an error if you use custom_target or generator outputs, instead
leaving it out of the typed pos args.

However, that support was specifically supposed to be there. It was only
an error in part of an if statement for handling old versions of
glib-compile-resources. The specific error it calls out is that we need
to manually parse the depfile at configure time, due to an external bug;
obviously this is impossible if the gresource is only created at build
time.

Reinstate the original error message check, and allow built outputs to
be used as compile_resources() inputs.

Fixes #10367

Author: eli-schwartz

mesonbuild/modules/gnome.py

@@ -371,7 +371,7 @@ def post_install(self, state: 'ModuleState', args: T.List['TYPE_var'], kwargs: '
             rv.append(script)
         return ModuleReturnValue(None, rv)
 
-    @typed_pos_args('gnome.compile_resources', str, (str, mesonlib.File))
+    @typed_pos_args('gnome.compile_resources', str, (str, mesonlib.File, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList))
     @typed_kwargs(
         'gnome.compile_resources',
         _BUILD_BY_DEFAULT,
@@ -426,6 +426,13 @@ def compile_resources(self, state: 'ModuleState', args: T.Tuple[str, 'FileOrStri
                     ifile = os.path.join(state.environment.get_build_dir(), input_file.subdir, input_file.fname)
                 else:
                     ifile = os.path.join(input_file.subdir, input_file.fname)
+
+            elif isinstance(input_file, (build.CustomTarget, build.CustomTargetIndex, build.GeneratedList)):
+                raise MesonException('Resource xml files generated at build-time cannot be used with '
+                                     'gnome.compile_resources() in the current version of glib-compile-resources '
+                                     'because we need to scan the xml for dependencies due to '
+                                     '<https://bugzilla.gnome.org/show_bug.cgi?id=774368>\nUse '
+                                     'configure_file() instead to generate it at configure-time.')
             else:
                 ifile = os.path.join(state.subdir, input_file)