[io] Fix std::complex on Windows

[bellenot]

This PR fixes #20312
Fixes the following warnings:

2328: Warning in <TStreamerInfo::Build>: _Complex_base<double,_C_double_complex>: base class _C_double_complex has no streamer or dictionary it will not be saved
2328: Warning in <TStreamerInfo::Build>: complex<double>: base class _Complex_base<double,_C_double_complex> has no streamer or dictionary it will not be saved

[linev]

If problem resolved one can remove special windows ref files.

[bellenot]

If problem resolved one can remove special windows ref files.

Oh right, indeed, thanks!

[linev]

For me changes are fine, but probably @pcanal want comment as well

[linev]

Seems to be all tests from roottest/root/io/complex no longer failing on Windows.
One need to remove ${WILLFAIL_ON_WIN32} there

[pcanal]

This does remove the warnings by generating the dictionary but I think this results in files that are not readable on Linux. I.e. one might not be able to load the std::complex from the Windows produce file into the Linux std::complex object.

For example, contrast he output of:

TClass::GetClass("std::complex<int>")->GetStreamerInfo()->ls();

on both platform.

[bellenot]

I'll check

[bellenot]

So here is the output on Windows:

C:\root-dev\build\x64\relwithdebinfo>root -l
root [0] TClass::GetClass("std::complex<int>")->GetStreamerInfo()->ls();

StreamerInfo for class: complex<int>, checksum=0x1bd95fcc
  _Complex_base<int,_Complex_value<int> > BASE            offset=  0 type= 0
  int            _real           offset=  0 type= 3
  int            _imag           offset=  4 type= 3
   i= 0, _Complex_base<int,_Complex_value<int> > type=  0, offset=  0, len=1, method=0
   i= 1, _real           type= 23, offset=  0, len=2, method=0 [optimized]
root [1]

I'll try on Linux once the build is over (on a VM with 4 cores...)

[bellenot]

On Linux:

[bellenot@alma9-bb relwithdebinfo]$ root -l
root [0] TClass::GetClass("std::complex<int>")->GetStreamerInfo()->ls();

StreamerInfo for class: complex<int>, checksum=0x55a2a7c3
  int            _real           offset=  0 type= 3
  int            _imag           offset=  4 type= 3
   i= 0, _real           type= 23, offset=  0, len=2, method=0 [optimized]
root [1]

So if I understand correctly, this PR solves std::complex on Windows, but makes it incompatible with other platforms.
Then what do you suggest?

[github-actions]

Test Results

    22 files      22 suites   3d 18h 42m 58s ⏱️
 3 739 tests  3 735 ✅   2 💤 2 ❌
80 304 runs  80 098 ✅ 202 💤 4 ❌

For more details on these failures, see this check.

Results for commit d7372e1.