Unexpected (or unnecessary) dependency (once_cell) because of `target_os` incorrect usage

[boozook]

aHash/Cargo.toml

Lines 89 to 90 in 4b73276

	[target.'cfg(not(all(target_arch = "arm", target_os = "none")))'.dependencies]
	once_cell = { version = "1.18.0", default-features = false, features = ["alloc"] }

FYI target_os can be any random name, including name of some custom or rare OS.
And there is should no automated decision "to take once_cell with alloc or not to take" depending on target_os (or specifically on target_os=none) - this is the error.
I'm sure this should be a feature, but definitely not a relation to target_os or target_env.

As a hot-fix I could propose to use target-family (src-doc) instead, because it's more generic and can be array-of-values defined in the target.

[zakarumych]

I would say one should not use not(target_os) for this purpose.

Using dependencies FOR specific OS sounds alright.

So I propose replacing negative condition with explicit list of target_os or target_family.