[clang] [clang] [MinGW] Explicitly always pass the -fno-use-init-array (PR #68571)

[Martin Storsjö via cfe-commits]

mstorsjo wrote:

> Whatever we decide to do on the LLVM side, this seems fine for the clang side.

Yes, this bit should be fine in any case.

> It looks like clang uses the value of UseInitArray for some ObjC stuff, in addition to passing it to the backend, so we need the right value in clang in any case.

Indeed, having the correct picture is good, if there's logic that depends on it. For the ObjC case, the code actually looks like this:
```cpp
    if (CGM.getTriple().isOSBinFormatCOFF())
        InitVar->setSection(".CRT$XCLz");
    else
    {
      if (CGM.getCodeGenOpts().UseInitArray)
        InitVar->setSection(".init_array");
      else
        InitVar->setSection(".ctors");
    }
```
So in that sense, it doesn't really matter here. (The `.CRT$...` sections do work on mingw too, even if `.ctors` normally is used.)

https://github.com/llvm/llvm-project/pull/68571