compat.sycl-runtime

// What compat.sycl-runtime is asserted to do.
//
// A machine with no GPU is a legitimate configuration and is what every runner
// in this repository is, so the test cannot require a device. It asserts the
// properties that hold on both kinds of machine.
//
//   1. The package resolves, builds and links. The failure this package exists
//      to prevent is a RUNTIME one -- `libsycl.so.9 not found on the search
//      path this artifact will actually use` -- so linking alone is not the
//      whole assertion.
//
//   2. THE FARM IS SUFFICIENT FOR ITS OWN MEMBERS. For every versioned library
//      in the farm, every SONAME in its DT_NEEDED is either in the farm too or
//      is one of the three the artifact itself has already loaded.
//
//   3. `libsycl.so.9` loads and carries the entry point every SYCL program
//      reaches the runtime through. Resolving a file is not the same as it
//      being the runtime.
//
// WHY (2) IS A DT_NEEDED WALK AND NOT `dlopen` OF EACH MEMBER, which is what
// this test did first: dlopen measures the PROCESS, and the process has more
// on its search path than this package put there. Measured -- with an OpenCL
// …