For some reason, The cargo test for the cpp driver test puts the
libslint_cpp.so library in the `deps` foilder, in addition to the
cdynlib which is generated in the normal target folder. So we end
up with two .so.
We need to have the cpp lib as a dependency because its metadata give us the
metadata on where to find the headers.
Ideally it should be an artifact dependency but this is not yet existing
Since cargo sets the LD_LIBRARY_PATH or the PATH env variable when
running the test, running the runtime built binaries work by taking
the library that is in the deps folder.
instead of in the sixtyfps! macro, so se actually see where the error is in
the generated code.
This also expose a bunch of warning that were not being taken care on.
