build(linux): fix compilation with Clang

[AngryLoki]

Description

Clang 20.1.7 fails with the following error:

/var/tmp/portage/net-misc/sunshine-2025.122.141614/work/Sunshine-2025.122.141614/src/platform/linux/misc.cpp:427:25: error: variable-sized object may not be initialized
  427 |       struct iovec iovs[(send_info.headers ? std::min(seg_max, send_info.block_count) : 1) * max_iovs_per_msg] = {};
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As VLAs are not part of the C++ standard, Clang barely supports their features. However, simple memset fixes the issue.

Issues Fixed or Closed

• N/A

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

[sonarqubecloud]

Quality Gate failed

Failed conditions
1 New issue
B Maintainability Rating on New Code (required ≥ A)
1 New Code Smells (required ≤ 0)

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[Copilot]

Pull Request Overview

This PR fixes a Clang compilation error by replacing inline initialization of variable-length arrays with explicit memset zeroing.

• Removed direct initializer usage for VLAs and added memset calls to clear memory.
• Applied the same fix to both iovs and msgs arrays in different code blocks.

Comments suppressed due to low confidence (2)

src/platform/linux/misc.cpp:427

• Consider adding a short inline comment explaining that memset is used here to zero initialize the variable-length array because direct initializer lists are not supported by Clang.

      struct iovec iovs[(send_info.headers ? std::min(seg_max, send_info.block_count) : 1) * max_iovs_per_msg];

src/platform/linux/misc.cpp:511

• Similarly, add a brief comment alongside the memset calls for msgs and iovs to clarify that this approach is a workaround for Clang's limitations with variable-length array initialization.

      struct mmsghdr msgs[send_info.block_count];