missing #if defined(__cplusplus) in netcdf_dispatch.h

[edhartnett]

In some of our header files (ex. hdf5dispatch.h) we have the if defined(__cplusplus) business around all our prototypes, like this:

#if defined(__cplusplus)
extern "C" {
#endif

   /* All function prototypes. */

#if defined(__cplusplus)
}
#endif

On other header files, like netcdf_dispatch.h, we don't have that.

Should we have that for all prototypes in all header files? I believe the answer is yes.

These are needed for C++ compilers to compile the netCDF C library, as described here: https://stackoverflow.com/questions/3789340/combining-c-and-c-how-does-ifdef-cplusplus-work

While this does not seem like a pressing need, there's no reason we should not be consistent and do this properly in all header files.

[edhartnett]

Actually this is just in netcdf_dispatch.h. I have a fix and it will be in my next PR.

[edhartnett]

OK, this fix never made it, due to other issues with the PR. So I will submit a PR just for this...