cstyle.pl warnings

getting warning when running `cstyle.pl`:
```
Unescaped left brace in regex is deprecated here (and will be fatal in Perl 5.30), passed through in regex; marked by <-- HERE in m/(?:(?:\b(?:enum|struct|union)\s*[^\{]*)|(?:\s+=\s*)){ <-- HERE / at ../cstyle.pl line 760.
```
Either the Perl program needs to be fixed or replaced by something else.