Is this a compiler issue?

[DLearner]

Hi

This uses DMD64 D Compiler v2.111.0, using -betterC, under 
Windows 10.

With the two commented lines in place, results are as expected.
Uncomment those two lines, even though the variable is set but 
never used,
the program fails at the link stage with reference to a missing 
'_memsetn'.

Ideas?

```
extern(C) void main() {
    import core.stdc.stdio : printf;
    import testmod : sub1 , TestStruct;

    int IntVar1 = 5;


    TestStruct[1] TS1;

    TS1[0].VarAddr = &IntVar1;
    TS1[0].VarName = "IntVar1";
    TS1[0].VarInt = 3;
//   TS1[0].VarType = 'N';


    printf("ppm_th: Entered.\n");


    printf("ppm_th: Calling sub1...\n");
    sub1(TS1);
    printf("ppm_th: Returned from sub1.\n");


    printf("ppm_th: Exiting...\n");
}
```

The module 'testmod':

```
struct TestStruct {
    void*  VarAddr;
    string VarName;
    int    VarInt;
//   char   VarType;
}


void sub1(TestStruct[] parmTestStruct) {

    import core.stdc.stdio : printf;
    printf("sub1: Entered.\n");

    int* VarAddr;
    size_t wkIdx;


    for (wkIdx = 0; wkIdx < parmTestStruct.length; wkIdx = wkIdx + 
1) {

          VarAddr = cast(int*)(parmTestStruct[wkIdx].VarAddr);

          printf("*VarAddr = %d\n", *VarAddr);
          printf("\n");
    }
    printf("sub1: Exiting...\n");
}
```