Since commit
124a67e96ecab5495c0f17b6875d53dfd67ff137: configure: add set -u
all variables must be set before their expansion are attempted. These
2 variables: "platform" and "linker_resolves_library_dependencies" were
not given value in the final 'else' branch when platform check failed
due to unrecognized kernel name (output of `uname`). Now those two are
given reasonable non-empty values.