|WARNING| cfgfile: fix isspace() undefined behavior

[dpdklab at iol.unh.edu]

Test-Label: ai-code-review
Test-Status: WARNING
https://dpdk.org/patch/172056

_AI Code Review_

=== Patch Review: series.patch (via Claude) ===
Review date: 2026-10-24

# DPDK Patch Review

## ERRORS

**Missing semicolon in while loop**
Line 109: The while loop is missing a semicolon before the comment.

```c
/* Bad - syntax error */
while (isspace((unsigned char)str[start]) && start < newlen)
    start++
    ; /* do nothing */

/* Good - semicolon on same line as increment */
while (isspace((unsigned char)str[start]) && start < newlen)
    start++;
```

This would cause a compilation failure.

---

## Review Summary

The patch correctly addresses undefined behavior in the `isspace()` calls by casting char arguments to unsigned char. This is a real bug: signed char values >= 0x80 produce negative int values when promoted, causing out-of-bounds table access in ctype functions. The fix matches the established pattern already used elsewhere in DPDK.

However, the patch introduces a syntax error that would prevent compilation.

Review-Result: ERROR