Description

Variable-length arrays are a C construct. clang supports that as a non-standard extension. This changes the code to use std::vector instead.

I noticed that this warning started to pop up when we migrated to clang-20.

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)