FWIW I noticed two strange things about the new 64 bits OS X Instant Client:
The zip has been refreshed. I downloaded it in February and it was 61MB at the time. I downloaded again today and the file is 62.3MB. My C++ program was failing with a trap 6 with the old version but it works with the new one! The weird thing is that the version number did not change. Both zip files are 220.127.116.11.0.
I had to create a directory called /ade/b/2649109290/oracle/rdbms/lib/ and copy all the files into it. Otherwise I get the following error when running my program:
Library not loaded: /ade/b/2649109290/oracle/rdbms/lib/libocci.dylib.11.1