Prepare OPM for DUNE 2.10

[blattms]

DUNE_VERSION_NEWER has been removed. Falling back to DUNE_VERSION_GTE which exists since at least DUNE 2.7.

Removed switches for older version than 2.7.

[akva2]

So this is basically the same thing i do in the bump to 2.9 required, except the other way around, ie, it keeps support for older dune.

[blattms]

So this is basically the same thing i do in the bump to 2.9 required, except the other way around, ie, it keeps support for older dune.

I am not sure I understand this comment. The macro DUNE_VERSION_GTE is there from at least 2.7. Hence there is no bumping here. We just make sure that it also compiles with 2,10 which dropped the DUNE_VERSION_NEWER macro.

Note that DUNE_VERSION_NEWER means the at least the specified version is required. SO NEWER is a bit misleading. If that is 2.7 then the version needs to be >=2.7

[akva2]

The conditions you introduce is the same starting in dune 2.8, so you basically add stuff to handle 2.7. i just removed the 2.7 support thus we need none of the DUNE_VERSION_NEWER / DUNE_VERSION_GTE stuff. Strictly speaking my PR bumps to 2.8 required, but I thought we'd go for 2.9 since that is the version we use on every platform (ignoring the temporary rh7 2.8 for equinor).

[blattms]

Making this draft until i have a compiling version

[blattms]

I still don't get it. I test >=2.7 (GTE)and not >2.7 (GT).

Anyway, as it turns out we do not compile with 2.7 anyway because of #5595

[akva2]

I know that. As I said, it's the opposite approach of mine.
I removed existing checks because I dropped 2.7 support. You add additional checks to make 2.7 still work (if we ignore the other issue).

[blattms]

I see. Well, it now works with 2,7 -2.10 to make @totto82 happy.