Question about SHExpandLSQ opt parameter #537

There is no discussion section, so filing an issue.

One of our users is seeing:

 Warning --- SHExpandLSQ
 Consider changing parameter value of OPT to          128
  and recompiling the SHTOOLS archive.

I presume it's referring to this:

    integer(int32), parameter :: opt = 80

Could we get any more information about this? What are the implications of changing (or not changing) this? Why does it need to be a compile time parameter?

Thanks!