[Issue 24501] [REG2.107] imported mixin opCmp member function not found for a < b

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=24501

--- Comment #1 from johanengelen at weka.io ---
Selective import works around the issue somehow:
```
        import opcmp : DefineOpCmp;
```

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