fix(carbon-react): add compat styles to package (#9661)

Author: joshblack

packages/carbon-react/scss/compat/_theme.scss

@@ -0,0 +1,9 @@
+// Code generated by @carbon/react. DO NOT EDIT.
+//
+// Copyright IBM Corp. 2018, 2018
+//
+// This source code is licensed under the Apache-2.0 license found in the
+// LICENSE file in the root directory of this source tree.
+//
+
+@forward '@carbon/styles/scss/compat/theme';

packages/carbon-react/scss/compat/_themes.scss

@@ -0,0 +1,9 @@
+// Code generated by @carbon/react. DO NOT EDIT.
+//
+// Copyright IBM Corp. 2018, 2018
+//
+// This source code is licensed under the Apache-2.0 license found in the
+// LICENSE file in the root directory of this source tree.
+//
+
+@forward '@carbon/styles/scss/compat/themes';

packages/carbon-react/tasks/build-styles.js

@@ -449,6 +449,20 @@ async function build() {
           },
         ],
       },
+      {
+        type: 'directory',
+        filepath: 'compat',
+        files: [
+          {
+            type: 'file',
+            filepath: '_theme.scss',
+          },
+          {
+            type: 'file',
+            filepath: '_themes.scss',
+          },
+        ],
+      },
     ],
   };
   const files = collect(styles);