Cannot build the MPI ABI on macOS 26.2 arm64

[dalcinl]

The configure-generated mpichconf.h on macOS contains the following bad defines

grep 'MPIR_COMPLEX$' workdir/src/include/mpichconf.h
#define MPIR_CXX_DOUBLE_COMPLEX_INTERNAL MPIR_COMPLEX
#define MPIR_CXX_FLOAT_COMPLEX_INTERNAL MPIR_COMPLEX

On Linux, I see the correct MPIR_COMPLEX64/32.

/Users/dalcinl/Devel/mpi-publish/package/source/src/mpi/datatype/typeutil.c:82:5: error: use of undeclared identifier 'MPIR_COMPLEX'; did you mean 'MPIR_COMM'?
   82 |     type_name_entry(CXX_FLOAT_COMPLEX,  COMPLEX),         /* 0x34 */
      |     ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/mpi/datatype/typeutil.c:24:45: note: expanded from macro 'type_name_entry'
   24 | #define type_name_entry(x_, g_) { MPI_##x_, MPIR_##x_##_INTERNAL, MPIR_DT_GROUP_##g_, "MPI_" #x_ }
      |                                             ^
<scratch space>:109:1: note: expanded from here
  109 | MPIR_CXX_FLOAT_COMPLEX_INTERNAL
      | ^
./src/include/mpichconf.h:823:41: note: expanded from macro 'MPIR_CXX_FLOAT_COMPLEX_INTERNAL'
  823 | #define MPIR_CXX_FLOAT_COMPLEX_INTERNAL MPIR_COMPLEX
      |                                         ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/include/mpir_objects.h:142:5: note: 'MPIR_COMM' declared here
  142 |     MPIR_COMM = 0x1,
      |     ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/mpi/datatype/typeutil.c:83:5: error: use of undeclared identifier 'MPIR_COMPLEX'; did you mean 'MPIR_COMM'?
   83 |     type_name_entry(CXX_DOUBLE_COMPLEX, COMPLEX),         /* 0x35 */
      |     ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/mpi/datatype/typeutil.c:24:45: note: expanded from macro 'type_name_entry'
   24 | #define type_name_entry(x_, g_) { MPI_##x_, MPIR_##x_##_INTERNAL, MPIR_DT_GROUP_##g_, "MPI_" #x_ }
      |                                             ^
<scratch space>:114:1: note: expanded from here
  114 | MPIR_CXX_DOUBLE_COMPLEX_INTERNAL
      | ^
./src/include/mpichconf.h:820:42: note: expanded from macro 'MPIR_CXX_DOUBLE_COMPLEX_INTERNAL'
  820 | #define MPIR_CXX_DOUBLE_COMPLEX_INTERNAL MPIR_COMPLEX
      |                                          ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/include/mpir_objects.h:142:5: note: 'MPIR_COMM' declared here
  142 |     MPIR_COMM = 0x1,
      |     ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/mpi/datatype/typeutil.c:84:5: error: use of undeclared identifier 'MPIR_ALT_COMPLEX'
   84 |     type_name_entry(CXX_LONG_DOUBLE_COMPLEX, COMPLEX),    /* 0x36 */
      |     ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/mpi/datatype/typeutil.c:24:45: note: expanded from macro 'type_name_entry'
   24 | #define type_name_entry(x_, g_) { MPI_##x_, MPIR_##x_##_INTERNAL, MPIR_DT_GROUP_##g_, "MPI_" #x_ }
      |                                             ^
<scratch space>:119:1: note: expanded from here
  119 | MPIR_CXX_LONG_DOUBLE_COMPLEX_INTERNAL
      | ^
./src/include/mpichconf.h:826:47: note: expanded from macro 'MPIR_CXX_LONG_DOUBLE_COMPLEX_INTERNAL'
  826 | #define MPIR_CXX_LONG_DOUBLE_COMPLEX_INTERNAL MPIR_ALT_COMPLEX
      |                                               ^
/Users/dalcinl/Devel/mpi-publish/package/source/src/mpi/datatype/typeutil.c:119:23: error: invalid application of 'sizeof' to an incomplete type 'struct MPIR_Datatype_builtin_entry[]'
  119 |     MPIR_Assert(sizeof(MPIR_Internal_types) / sizeof(MPIR_Internal_types[0]) ==
      |                       ^~~~~~~~~~~~~~~~~~~~~
/Users/dalcinl/Devel/mpi-publish/package/source/src/include/mpir_assert.h:41:24: note: expanded from macro 'MPIR_Assert'
   41 |         if (unlikely(!(a_))) {                         \
      |                        ^~
/Users/dalcinl/Devel/mpi-publish/package/source/src/mpl/include/mpl_base.h:81:42: note: expanded from macro 'unlikely'
   81 | #define unlikely(x_) __builtin_expect(!!(x_),0)
      |                                          ^~
4 errors generated.
make[3]: *** [src/mpi/datatype/lib_libpmpi_abi_la-typeutil.lo] Error 1

[hzhou]

@dalcinl Could locate and upload the config.log?

[hzhou]

In case the complex types are not available in the C++ compiler by default, #7720 should fix the issue.