* add almost all the input parameter state to the hash
   - missing items are the detected MSVC installation on Windows
     and detected libc installation on POSIX
   - also missing are C files and .h files that libclang finds
 * artifacts are created in global cache directory instead of
   zig-cache.
   - exception: builtin.zig is still in zig-cache
 * zig run uses the new cache correctly
 * zig run uses execv on posix systems