deal with .dSYM on os x

[boggle]

When building shared libs on os x gcc generates separate .dSYM directories that contain out-factored symbol information. This is a bit ugly and different from the other platforms.

We need to investigate/decide what to do with it: leave it, delete it, somehow generate normal libs with included symbols. This also effects cargo which needs to know wether it should copy these files and possibly where.

[jdm]

dSYMs can be important for gdb support. For example, there's a bug in gdb trunk that prevents debugging support from working on os x unless there's a dSYM present. One of my side projects is working on fixing that, but until then it would be nice not to kill that option entirely.

[catamorphism]

Closing because it sounds like this is necessary for gdb support. Reopen if you can clarify an approach that doesn't break gdb :-)