build fails with icu 75

[andyrtr]

Building with recent icu 75.1/harfbuzz-icu give this build failure:

   Compiling tracing v0.1.40
The following warnings were emitted during compilation:

warning: [email protected]: In file included from /usr/include/unicode/ubidi.h:26,
warning: [email protected]:                  from layout/xetex-XeTeXLayoutInterface.cpp:36:
warning: [email protected]: /usr/include/unicode/localpointer.h:561:26: error: ‘auto’ parameter not permitted in this context
warning: [email protected]:   561 | template <typename Type, auto closeFunction>
warning: [email protected]:       |                          ^~~~
warning: [email protected]: /usr/include/unicode/localpointer.h:573:76: error: template argument 2 is invalid
warning: [email protected]:   573 |     explicit LocalOpenPointer(std::unique_ptr<Type, decltype(closeFunction)> &&p)
warning: [email protected]:       |                                                                            ^
warning: [email protected]: /usr/include/unicode/localpointer.h:583:78: error: template argument 2 is invalid
warning: [email protected]:   583 |     LocalOpenPointer &operator=(std::unique_ptr<Type, decltype(closeFunction)> &&p) {
warning: [email protected]:       |                                                                              ^
warning: [email protected]: /usr/include/unicode/localpointer.h:599:59: error: template argument 2 is invalid
warning: [email protected]:   599 |     operator std::unique_ptr<Type, decltype(closeFunction)> () && {
warning: [email protected]:       |                                                           ^
warning: [email protected]: /usr/include/unicode/ubidi.h:579:1: note: invalid template non-type parameter
warning: [email protected]:   579 | U_DEFINE_LOCAL_OPEN_POINTER(LocalUBiDiPointer, UBiDi, ubidi_close);
warning: [email protected]:       | ^~~~~~~~~~~~~~~~~~~~~~~~~~~

error: failed to run custom build command for `tectonic_xetex_layout v0.2.4 (/build/tectonic/src/tectonic-tectonic-0.15.0/crates/xetex_layout)`

Caused by:
  process didn't exit successfully: `/build/tectonic/src/tectonic-tectonic-0.15.0/target/release/build/tectonic_xetex_layout-2d264a57173811f7/build-script-build` (exit status: 1)