zig cc: fix wrong flag name from earlier commit

In dfe942024461a3598fc872ea79e7859a8744b550, I made a typo. This commit
corrects it. I tested this commit via a patch to zig-bootstrap.
f8f65aebe6Andrew Kelley committed on 1/9/2023, 9:59:19 PMparent3bc70ea
1 file changedLine totals unavailable