[Python] PyArrow C++ header files no longer always included in installed pyarrow

[asfimport]

We have a python build env var to control whether the Arrow C++ header files are included in the python package or not (PYARROW_BUNDLE_ARROW_CPP_HEADERS). This is set to True by default, and only in the conda recipe set to False.

After the cmake refactor, the Python C++ header files no longer live in the Arrow C++ package, and so should always be included in the python package, regardless of how arrow-cpp is installed.
Initially this was done, but it seems that #13892 removed this unconditional copy of the PyArrow header files to pyarrow/include. Now it is only copied if PYARROW_BUNDLE_ARROW_CPP_HEADERS is enabled.

Reporter: Joris Van den Bossche / @jorisvandenbossche
Assignee: Alenka Frim / @AlenkaF

Related issues:

• [Python] get_include() gives wrong directory in conda environment (relates to)

PRs and other links:

• GitHub Pull Request #14656

_{Note: This issue was originally created as ARROW-18340. Please see the migration documentation for further details.}

[asfimport]

Joris Van den Bossche / @jorisvandenbossche:
cc @kou @raulcd

[asfimport]

Kouhei Sutou / @kou:
Issue resolved by pull request 14656
#14656