I've been trying to run some benchmarks and see how `-O2`, `-O3` and `-Ofast` compare.
However, when compiling with either `-d:release` or `-d:danger`, it seems as if Nim sticks an `-O3` regardless of what options have been passed via `--passC:`. So... the question is: is there any way to keep e.g. the `-d:release` option and actually change the optimization flags to something other than `-O3`?
