rispc vs ispc_rt vs ispc

A build-time dependency for cargo build scripts to assist in invoking Intel's ISPC compiler to compile a static archive to be linked into rust code.

A runtime dependency for linking Rust code with pre-built ISPC binaries and Rust bindings. These modules and bindings should be built with ispc_compile.

A build-time dependency for Cargo build scripts to help with compiling and linking to ISPC code and generating Rust bindings for the resulting library. This crate is a meta-crate for the ispc_compile and ispc_rt crates, which provide the actual functionality for building ISPC code and generating bindings, and importing those bindings into Rust.