Re: [PATCH] perf: do allow `GIT_PERF_*` to be overridden again

> The original patch in this thread did something like:
>
>   git_perf_settings=$(...pull GIT_PERF_* from env...)
>    . ../test-lib.sh
>   eval "$git_perf_settings"
>
> That is, we stash away the environment, then load test-lib.sh, which
> overwrites the environment, and then we restore (some of) the original
> values.
>
> In that merge, the test-lib.sh inclusion is moved (and in fact is now
> accompanied by an explicit inclusion of GIT-BUILD-OPTIONS), and we now
> have:
>
>    . "$GIT_BUILD_DIR"/GIT-BUILD-OPTIONS
>    . "$GIT_SOURCE_DIR"/t/test-lib.sh
>    git_perf_settings=$(...)
>    eval "$git_perf_settings"
>
> Which of course does nothing. We need to set $git_perf_settings before
> those other source lines (and the eval must remain after them).