meson: Add tests for generated pkg-config files

Ensure things are generated as we expect and avoid we regress on that.

gmodule/tests/meson.build

@@ -124,3 +124,31 @@ foreach test_name, extra_args : gmodule_tests
     suite : suite,
   )
 endforeach
+
+if have_bash and have_pkg_config
+  modules = [
+    'gmodule-no-export-2.0',
+    'gmodule-export-2.0',
+    'gmodule-2.0',
+  ]
+
+  foreach module: modules
+    test(module + '-pkg-config',
+      bash,
+      args: [
+        '-xe', '-c',
+        '\n'.join([
+          'pkg-config --validate ' + module,
+          'test "$(pkg-config --modversion @0@)" = "@1@"'.format(
+            module, glib_version),
+          'test "$(pkg-config --variable=prefix @0@)" = "@1@"'.format(
+            module, get_option('prefix')),
+        ]),
+      ],
+      suite: ['gmodule', 'no-valgrind', 'pkg-config'],
+      env: {
+        'PKG_CONFIG_PATH': meson.project_build_root() / 'meson-private',
+      },
+    )
+  endforeach
+endif