linker can't find the C function wmemove when -mscrtlib=msvcrt

[dlangBugzillaToGithub]

Suleyman Sahmi (سليمان السهمي) reported this on 2019-12-19T03:08:50Z

Transferred from https://issues.dlang.org/show_bug.cgi?id=20456

Description

The following program fails to link.
```
import core.stdc.wchar_;
int main()
{
    wchar_t[10] a = void;
    wchar_t[10] b = void;
    wmemmove(a.ptr, b.ptr, 10);

    return 0;
}
```

compiled with: dmd test.d -m64 -mscrtlib=msvcrt

The equivalent C program succeds.
```
#include <wchar.h>

int main()
{
    wchar_t a[10];
    wchar_t b[10];
    wmemmove(a,b,10);

    return 0;
}
```

compiled with: cl test.c /MD