GeezerVison

When building a module that depends on another ITK module (e.g. RTK
depends on ITKCudaCommon), the ITK build cache is downloaded and
extracted once in the parent directory. build-module-deps.sh then
symlinks the module directory to that cache (ITKPythonPackage ->
../ITKPythonPackage) and used to re-run the full download-and-extract
flow inside the module directory.

Re-extracting in the module directory was problematic for two reasons:

- Redundant: the same cache was just extracted in the parent directory
  with the same arguments, and the module directory writes through the
  symlink into that same shared tree.

- Recent GNU tar (openat2 jailification, e.g. Ubuntu tar
  1.35+dfsg-4ubuntu0.2+) fails with 'Invalid cross-device link' (EXDEV)
  when extracting members under ITKPythonPackage/ because the symlink
  escapes the extraction root.

The module dependency build also registers the module (e.g. CudaCommon)
into the shared ITK build tree (ITK_DIR) it builds against, so the
registration must land in the tree the parent build reuses afterwards.
Building against a module-local copy instead of the shared tree breaks
serial module dependencies.

Fix: when the parent already holds the extracted cache, build the module
directly against the shared tree with
dockcross-manylinux-build-module-wheels.sh, without re-extracting it.
When no cache is available (standalone use of build-module-deps.sh),
keep the full download-and-extract-and-build path.

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