Build error from following default nixos instructions and -Werror

When building the RTS with the nixos instructions from the wiki (https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Linux#NixNixOS) if you enable Werror then the build fails with warnings from the rts.

For example

rts/Interpreter.c: In function ‘interpretBCO’:
rts/Interpreter.c:593:41: error:
     warning: ‘obj’ may be used uninitialized in this function [-Wmaybe-uninitialized]
                  debugBelch("Returning: "); printObj(obj);

Is this something I should worry about? Are there additional flags that I should pass to gcc in order to turn these warnings off?

The workaround is compile without -Werror and then turn it on once the rts has been compiled.

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	lowest
Resolution	Unresolved
Component	Compiler
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