Cleanup of equivalence checks

[zerothi]

This relates to Reference-ScaLAPACK/scalapack#162 (comment)

There it was suggested to replace:

if ( .not. X .and. Y .OR. X .and .not. Y)
if ( (.not. X .and. .not. Y) .OR. (X .and Y))

these could be replaced with:

.NEQV.
.EQV.

Would these changes be accepted here?

[martin-frbg]

This looks more like a matter of personal taste to me, rather than an actual cleanup ? Both idioms are equally valid and readable - a whitespace change that will need closer review than an actual whitespace one

[langou]

Thanks @zerothi for creating an issue so that we can discuss this, as opposed to a PR. Good to discuss it first. I have a weak opinion on this but my opinion is to leave the code as is. I think that, albeit verbose, the current code is slightly more readable (to me). So I am against the change. (Weak opinion though.) Other opinions welcome.

[zerothi]

Ok, let's not do anything then :)