re: https://github.com/Unidata/netcdf-c/issues/1502
If you plan to use any of the netcdf_XXX.h files, then it it is assumed
that you first include netcdf.h, followed by any netcdf_XXX.h files
you need. The EXTERNL (and other things) are defined in netcdf.h
so they should be available for use by the netcdf_XXX.h files.
This PR ensures that the above assumption is true. It also adds
some comments to that effect to the start of the netcdf_xxx.h files.
Partially address: https://github.com/Unidata/netcdf-c/issues/1056
Currently, some of the entries in the dispatch table
are conditional'd on USE_NETCDF4.
As a step in upgrading the dispatch table for use
with user-defined tables, we remove that conditional.
This means that all dispatch tables must implement the
netcdf-4 specific functions even if only to make them
return NC_ENOTNC4. To simplify this, a set of default
functions are defined in libdispatch/dnotnc4.c to provide this
behavior. The file libdispatch/dnotnc3.c is also relevant to
this.
The primary fix is to modify the various dispatch tables to
remove the conditional and use the functions in
libdispatch/dnotnc4.c as appropriate. In practice, all of the
existing tables are prepared to handle this, so the only
real change is to remove the conditionals.
Misc. Unrelated fixes
1. Fix some annoying warnings in ncvalidator.
Notes:
1. This has not been tested with either pnetcdf or hdf4 enabled.
When those are enabled, it is possible that there are still
some conditionals that need to be fixed.
