controlling callgrind instrumentation from D

[Stefan Koch]

On Friday, 10 September 2021 at 14:34:35 UTC, Stefan Koch wrote:
>
> ```d
> extern (c) void callgrind_start();
> extern (c) void callgrind_stop();
> extern (c) void callgrind_dumpstats();
> ```
>
Correction that's supposed to be:

```d
extern (C) void callgrind_start();
extern (C) void callgrind_stop();
extern (C) void callgrind_dumpstats();
```