COMP: Pinned CastXML 0.6.5 cannot parse gcc-toolset-14 `<limits>` (`_Float32`/`F32`) — blocks all manylinux_2_28 wheel builds

[hjmjohnson]

The CastXML 0.6.5 binary used by the manylinux_2_28 wheel builds cannot parse GCC 14's <limits>, so every Linux Python wrapping job fails for remote modules — on main, not only on PRs. CastXML 0.7.0 (2026-02-25) postdates the pin and the equivalent gcc-13 defect was fixed upstream, so bumping the pinned CastXML is the likely fix.

Failure detail and error text

manylinux_2_28 dockcross containers now ship gcc-toolset-14. GCC 14's <limits> uses the __glibcxx_float_n(32) macro family, which expands to F32 floating literal suffixes and __builtin_huge_valf32. CastXML 0.6.5's embedded Clang does not support these:

invalid suffix 'F32' on floating constant
typedef redefinition with different types ('float' vs 'struct __castxml_Float32_s')

Reported location: /opt/rh/gcc-toolset-14/root/usr/include/c++/14/limits:1989.

Scope of impact

• All 8 Linux Python wrapping jobs fail.
• Reproduced on module main branches — this is not introduced by any PR.
• Affects any ITK remote module that builds Python wheels on manylinux_2_28, i.e. the whole remote-module wheel fleet.
• First observed during CI triage of ITKMontage PR ENH: Update Windows download and build script #242 (merged 2026-04-15).

Upstream status and suggested fixes, in order of preference

• CastXML releases since the 0.6.5 pin: v0.6.9, v0.6.10 (2024-11-27), v0.6.11 (2025-02-11), v0.6.12/v0.6.13 (2025-08-28), v0.7.0 (2026-02-25).
• Upstream CastXML#251 "gcc-13.2.0 unknown type name _Float32" — CLOSED 2024-01-23. Same defect class, already fixed for gcc-13.

1. Bump the pinned CastXML binary in the wheel-build docker images to v0.7.0 (or ≥0.6.10) and re-run a Linux wrapping job. This is the expected fix and should be tried first.
2. If 0.7.0 still fails on gcc-14, file a fresh upstream issue at https://github.com/CastXML/CastXML with the limits:1989 reproducer.
3. Stop-gap: pin the dockcross image tags back to a gcc-toolset-13 revision.
4. Alternative: configure CastXML to use its own bundled Clang headers rather than the GCC toolset headers.