A small error in 'CheckLinkFlag' was resulting in `-Werror` being set as a CXXFLAG after the function was run. This patch fixes this. Change-Id: I786f81a4f94be0356573eb6d4673d04ee5aa844d Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/54863 Maintainer: Bobby Bruce <bbruce@ucdavis.edu> Reviewed-by: Gabe Black <gabe.black@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com>