See https://www.mpi-forum.org/docs/mpi-4.1/mpi41-report.pdf page 10

The following error message on JUWELS is fixed with this commit

vtkMPICommunicator.cxx:60    WARN| MPI had an error
------------------------------------------------
Invalid buffer pointer, error stack:
internal_Allgather(133): MPI_Allgather(sendbuf=0x1233940, sendcount=1, MPI_UNSIGNED_LONG, recvbuf=0x1233840, recvcount=1, MPI_UNSIGNED_LONG, MPI_COMM_WORLD) failed
internal_Allgather(85).: Buffers must not be aliased

Was used in one tool only, tclap/XorHandler.h is not available in tclap 1.4.

See https://github.com/boostorg/cmake/issues/45#issuecomment-1815570996.

headers are header-only libs, boost are compiled libs.

This guarantees floating-point -> text -> floating-point
roundtrip.

Those places, where the output precision was explicitly
set to 15-18 places, were replaced with max_digits10
precision.

This slightly simplifies code avoiding extra boolean variable.

These functions cannot return a dangling reference.

Remove unused version of findElementOrError with iterators
and error string.

Using in MPL shows no difference in runtime, one assembly
instruction is different.