if clang with latest Xcode supports -Wl,-rpath and older gcc on 10.7 supports setting the rpath that way, it might be a solution to fix mac compiles to work across 10.7 through 10.9 with one binary.

also, i think its mostly Solaris and non-gcc AIX that don't grok -Wl,-rpath

you should be able to roll some os-detection foo in here if that ever becomes a problem though...