Fix RelWithDebInfo build

[ayshuha]

This change adds the [[maybe_unused]] type alias to the variables defined and used in assertIsRecognized in GetEnv.hpp. This fixes -Wunused-variable errors raised when building with REL_WITH_DEB_INFO enabled, as we build our backend with -Wunused.

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[ThomasRaoux]

I'm guessing that won't be the only case. I'm not a big fan of the solution, feels very verbose. -Wunused-variable is not enabled right now, why are you running into those errors?

[ayshuha]

-Wunused-variable is not enabled right now, why are you running into those errors?

@ThomasRaoux We build our backend with -Wunused and we'd like to be able to build with RelWithDebInfo, and this is the only error that shows up in that mode.

I'm guessing that won't be the only case. I'm not a big fan of the solution, feels very verbose.

Alternatively I could change this to have the function assertIsRecognized and its uses wrapped with #ifndef NDEBUG macros

[lezcano]

Thank you! It'd be quite nice to build with -Wunused-variable even in the main build. Would you want to send a PR?

Edit. I see that Thomas has second thoughts, but on my side I'd vote to build always with -Wunused-variable. I find it quite useful.

[ThomasRaoux]

Thank you! It'd be quite nice to build with -Wunused-variable even in the main build. Would you want to send a PR?

Edit. I see that Thomas has second thoughts, but on my side I'd vote to build always with -Wunused-variable. I find it quite useful.

I'd be curious to see what it takes to enable -Wunused-variable. I doubt this is the only change needed