Cargo Features

ispc-downsampler has no features set by default.

[dependencies]
ispc-downsampler = { version = "0.4.0", features = ["ispc"] }
ispc = ispc_compile

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.

ispc_compile build ispc?