build failure on macOS 15 with PyPy 3.9

[DimitriPapadopoulos]

See #1164 (comment) and https://github.com/scikit-build/scikit-build-core/actions/runs/18679698422/job/53258305708?pr=1164:

      [250/322] Compiling C++ object
      numpy/_core/_multiarray_umath.pypy39-pp73-darwin.so.p/src_umath_string_ufuncs.cpp.o
      FAILED: [code=1]
      numpy/_core/_multiarray_umath.pypy39-pp73-darwin.so.p/src_umath_string_ufuncs.cpp.o
      c++ -Inumpy/_core/_multiarray_umath.pypy39-pp73-darwin.so.p
      -Inumpy/_core -I../numpy/_core -Inumpy/_core/include
      -I../numpy/_core/include -I../numpy/_core/src/common
      -I../numpy/_core/src/multiarray -I../numpy/_core/src/npymath
      -I../numpy/_core/src/umath -I../numpy/_core/src/highway
      -I/Users/runner/hostedtoolcache/PyPy/3.9.19/arm64/include/pypy3.9
      -I/Users/runner/work/_temp/setup-uv-cache/sdists-v9/pypi/numpy/2.0.2/CUApDXVKfmHEW0MAeMEzF/src/.mesonpy-vpm397jy/meson_cpu
      -fvisibility=hidden -fvisibility-inlines-hidden
      -fdiagnostics-color=always -DNDEBUG -Wall -Winvalid-pch -std=c++17
      -O3 -ftrapping-math -DNPY_HAVE_CLANG_FPSTRICT -DNPY_HAVE_NEON_VFPV4
      -DNPY_HAVE_NEON_FP16 -DNPY_HAVE_NEON -DNPY_HAVE_ASIMD
      -F/Applications/Xcode_16.4.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/Accelerate.framework
      -idirafter/Applications/Xcode_16.4.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks/Accelerate.framework/Headers
      -DACCELERATE_NEW_LAPACK -DHAVE_CBLAS '-DBLAS_SYMBOL_SUFFIX=$NEWLAPACK'
      -DNPY_INTERNAL_BUILD -DHAVE_NPY_CONFIG_H -D_FILE_OFFSET_BITS=64
      -D_LARGEFILE_SOURCE=1 -D_LARGEFILE64_SOURCE=1
      -D__STDC_VERSION__=0 -fno-exceptions -fno-rtti -MD -MQ
      numpy/_core/_multiarray_umath.pypy39-pp73-darwin.so.p/src_umath_string_ufuncs.cpp.o
      -MF
      numpy/_core/_multiarray_umath.pypy39-pp73-darwin.so.p/src_umath_string_ufuncs.cpp.o.d
      -o
      numpy/_core/_multiarray_umath.pypy39-pp73-darwin.so.p/src_umath_string_ufuncs.cpp.o
      -c ../numpy/_core/src/umath/string_ufuncs.cpp
      In file included from ../numpy/_core/src/umath/string_ufuncs.cpp:20:
      ../numpy/_core/src/umath/string_fastsearch.h:132:5: error: no type named
      'ptrdiff_t' in namespace 'std'; did you mean simply 'ptrdiff_t'?
        132 |     std::ptrdiff_t
            |     ^~~~~~~~~~~~~~
            |     ptrdiff_t
      /Applications/Xcode_16.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/17/include/__stddef_ptrdiff_t.h:18:26:
      note: 'ptrdiff_t' declared here
         18 | typedef __PTRDIFF_TYPE__ ptrdiff_t;
            |                          ^
[...]
      ninja: build stopped: subcommand failed.

      hint: This usually indicates a problem with the package or the build
      environment.
  help: `numpy` (v2.0.2) was included because `scikit-build-core[test-numpy]`
        (v0.1.dev1+gafd9d1eb0) depends on `numpy`

[LecrisUT]

Seems the issue is with availability/compiation of numpy wheel. They do provide wheels for pypy https://pypi.org/project/numpy/2.0.2/#files, and the macos14 should propagate forward to 15 afaiu, so not really sure why it fails.