Cargo Features

nt_version has no features set by default.

[dependencies]
nt_version = { version = "0.1.3", features = ["fallback"] }
fallback = winapi

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

winapi fallback?