Fix C lint errors

[stdlib-bot]

C Linting Failures

Linting failures were detected in the automated lint workflow run.

Workflow Details

• Run: https://github.com/stdlib-js/stdlib/actions/runs/15512872862
• Type: C Linting
• Date: 2025-06-08 00:17:23 UTC

Error Details

lib/node_modules/@stdlib/stats/base/sdsnanmean/benchmark/c/benchmark.length.c:110:39: warning: Uninitialized variable: x [uninitvar]
  v = stdlib_strided_sdsnanmean( len, x, 1 );
                                      ^

Pull Request Instructions

• Please use the following PR title format:
  "chore: fix C lint errors (issue #<ISSUE_NUMBER>)".
• Reference this issue in the "Related Issues" section of the PR body as "resolves #<ISSUE_NUMBER>".