Bug#1115195: adios2: GCC-15 causes autopkgtests to fail, blocking openmpi transition

[Alastair McKinstry]

Source: adios2
Version: 2.10.2+dfsg1-3
Severity: serious
Justification: 7
X-Debbugs-Cc: debian-science at lists.debian.org

Adios2 autopkgtests fail due to c++15 changes:
```

  IgnoreFlattenSteps = 0   default = 0
-----------------------------------------------------
/usr/include/c++/15/bits/stl_vector.h:1263: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = double; _Alloc = std::allocator<double>; reference = double&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.
/usr/include/c++/15/bits/stl_vector.h:1263: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = double; _Alloc = std::allocator<double>; reference = double&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.
/usr/include/c++/15/bits/stl_vector.h:1263: std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = double; _Alloc = std::allocator<double>; reference = double&; size_type = long unsigned int]: Assertion '__n < this->size()' failed.
--------------------------------------------------------------------------
prterun noticed that process rank 1 with PID 673208 on node sid exited on
signal 6 (Aborted).
--------------------------------------------------------------------------
```

There appears to be a C++ standards issue :
```
/tmp/autopkgtest.I1d3Aw/tree/examples/simulations/gray-scott/analysis/pdf-calc.cpp:311:42:   required from here
  311 |                 minmax_u = std::make_pair(*mmu.first, *mmu.second);
      |                            ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/15/bits/stl_pair.h:1164:5: note: parameter passing for argument of type ‘std::pair<double, double>’ when C++17 is enabled changed to match C++14 in GCC 10.1
 1164 |     make_pair(_T1&& __x, _T2&& __y)
      |     ^~~~~~~~~
```

C++11 is set when the library is compiled but not tests?

This is causing OpenMPI to fail to transition to testing.



-- System Information:
Debian Release: 13.1
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.43+deb13-amd64 (SMP w/4 CPU threads; PREEMPT)
Locale: LANG=en_IE.UTF-8, LC_CTYPE=en_IE.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_IE.UTF-8), LANGUAGE=en_IE:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled