Some changes to the C++ code to hopefully fix compilation on MacOS.
1.2.5
Added ability to suppress warning about missing data file.
1.2.4
Setting `Model="IGRF"` uses the internal field model without any external field contributions.
1.2.3
Hopefully fixed some building issues on Windows 10/11
1.2.2
Updated Windows-DLL-related code. It appears that newer versions of Python might not be searching $PATH for DLLs, so I have added a function to scan for libstdc++*.dll and use that path.
1.2.1
Fixed bug in Fortran code which requires the `-fallow-argument-mismatch` argument which doesn't appear to be available on all Fortran compilers.