Fix setting of use_szlib

[gsjaardema]

The USE_SZLIB symbol only appeared one time in this file in the entire project. I think that USE_SZIP is the intended symbol.

[edwardhartnett]

Umm are we really sure?

Yes sometimes it's szip and sometimes szlib. That's because HDF5 makes the same error of sometimes calling it one and sometimes the other. And it causes me a lot of problems!

But are you sure this is a correct replacement?

[gsjaardema]

This was the only instance of USE_SZLIB in the entire NetCDF code base, so there was no way that it could be set unless I am overlooking something... It is also the symbol that is used for the has_szlib setting in libnetcdf.settings

[gsjaardema]

Clarification -- it USE_SZIP is the symbol that is used to set the symbol that is used in libnetcdf.settings

[DennisHeimbigner]

In nc-config.in, the corresponding symbol tracks to HAS_SZLIB from configure.ac.
In configure.ac, this is set by looking for this:

if test "x$ac_cv_func_H5Z_SZIP" = xyes; then
so, it appears that SZLIB == SZIP.

[DennisHeimbigner]

There is clearly a difference between the nc-config generated by CMake
and the one generated by Automake. I bet that there are other discrepencies.

[WardF]

Thanks @gsjaardema . Something has gotten dropped somewhere, this is the second change in the last day that I would swear was merged in but clearly wasn't. Doing some sleuthing locally, and in the meantime I'll get this merged when the travis checks finish. Thanks!

[gsjaardema]

@WardF Yes, I thought this used to be working and was surprised when I tried it again and it wasn't...

[gsjaardema]

@DennisHeimbigner re differences -- One major difference is that --has-nczarr and --has-s3-sdk are only in autotools.

I think the rest of the options are the same...

[edwardhartnett]

Thanks Greg as always for all that you do to make netCDF bullet-proof!! ;-)

[DennisHeimbigner]

I will add to CMake version.