sprintf deprecated

"Use snprintf if available as some compilers (clang 14.0) issue deprecation warnings for sprintf"

```
libs/icl/example/toytime.hpp: sprintf(repr, "%3s:%02d:%02d", getDayString().c_str(), getHours(), getMinutes());
```

Start at libs/icl/example/toytime.hpp and inspect the shown sprintf call; reproduce the clang 14.0 deprecation warning if the project setup permits. Done means the example no longer triggers that warning while preserving its time representation.

Written by the indexing model from the issue text.