Using handheld class in the script, it is impossible to build to WSA, WP81 platforms. Getting error in the console: "The name 'Handheld' does not exist in the current context".

Issue reproducible from 4.6.4 to 4.6.9. Builds and runs fine from Unity 5.0;

Repro steps:
1. open "handheld_test.zip";
2. try to build it to WP81 or WSA;
3. error occurs in the console "The name 'Handheld' does not exist in the current context";