change in header files to make things better for C++? about erfa

[mhvk]

@scottransom - thanks very much for checking. I'm pretty sure this would not pose any problem at all for us, and, if there is some breakage (more likely in pyerfa than here), it would be trivial to fix.

[scottransom]

Great. Thanks for the quick response, @mhvk !

[rmathar]

In the recent iausofa C library (release 18) the macro definitions have been assembled in sofam.h to avoid (namespace) collision with user code.

[mhvk]

@rmathar - yes, indeed, and we've adjusted as necessary. It didn't cause much trouble, as foreseen, and really most of our discussion was whether the macros were sufficiently part of the API that we should bump the major version number - we decided in the end that it was, since in pyerfa we explicitly expose the constants in sofam.h.

Anyway, this is done and all is good, so I'll close this issue.