[fortran, patch] Remove unused elements in array argument to set_options

[Steven G. Kargl]

On Mon, Dec 19, 2016 at 11:29:45PM +0100, FX wrote:
> > Thinking out loud here.  I wonder, however, if we want
> > to future proof the library against changes to the
> > options passed by having a few spare unused entried 
> > available.  This of course only helps if a new option
> > needs to be added.  It does nothing for removal.
> 
> That’s actually the way gfortran_set_options() works, to ensure that we can add options in the future: in main() we allocate an array of values, and pass that array and its size to gfortran_set_options(). gfortran_set_options() then deals with the number of options passed, meaning if an older program calls a newer library, the runtime will simply use default values for all options there were not passed.
> 
> And when we remove options, we simply pass zero values in their stead — until we break the ABI, when we clean up everything.
> 
> Patch committed, thanks for reviewing.
> 

Thanks for the detailed explanation.  

-- 
Steve
http://troutmask.apl.washington.edu/~kargl/
 2. https://www.youtube.com/watch?v=Py6d6o2jbaE
 1. https://www.youtube.com/watch?v=6hwgPfCcpyQ