plt/racket — pull request #754 by tohammer (2014-08-18 13:15:58+00:00)
Title: fix cross compile on QNX

got broken in 2e284cc78357ccc4a63aae7603682b0344bfc58f
The racket version of libunwind is not compatible with QNX but old-style stacktraces are still working with the default gcc version