`--enable-deterministic-archives` is a GNU specific strip flag and
causes other strip implementations (for example LLVM's, see #138013)
to fail. Since strip failures are ignored, this means that stripping
doesn't work at all in certain situation (causing unnecessary
dependencies etc.).
To fix this, no longer pass `--enable-deterministic-archives`
unconditionally, but instead add it in a GNU binutils specific strip
wrapper only.
`commonStripFlags` was only used for this flag, so we can remove
it altogether.
Future work could be to make a generic strip wrapper, with support for
nix-support/strip-flags-{before,after} and NIX_STRIP_FLAGS_{BEFORE,AFTER}.
This possibly overkill and unnecessary though -- also with the
additional challenge of incorporating the darwin strip wrapper somehow.
