pub fn append_extra_kconfig_suffix(cache_key: &mut String, extra: Option<&str>)Expand description
Append the -xkc{extra_hash} segment to a cache key built around
the bare baked-in suffix (...-kc{baked_hash}), bringing it to the
two-segment shape produced by crate::cache_key_suffix_with_extra.
local_source and git_clone populate acquired.cache_key against
the bare crate::cache_key_suffix which carries only the baked-in
hash. With --extra-kconfig set, the cache lookup and the
post-build store must target the extras-aware slot — this helper
performs the plain string append so both binaries share one merge
path. Plain append (vs rewriting the suffix) preserves the upstream
key prefix exactly and is robust to any future shape change in the
head segments. No-op when extra is None.