Use dladdr() on the fixed frameAddress
Use dladdr() on the fixed frameAddress

I'm pretty sure this makes no difference except in the case of the first
frame in libdyld.dylib because the _start and start addresses are only 4
bytes apart.

joshdholtz/bugsnag-cocoa,joshdholtz/bugsnag-cocoa,joshdholtz/bugsnag-cocoa,segmentio/bugsnag-cocoa,joshdholtz/bugsnag-cocoa,bugsnag/bugsnag-cocoa,bugsnag/bugsnag-cocoa,joshdholtz/bugsnag-cocoa,bugsnag/bugsnag-cocoa,bugsnag/bugsnag-cocoa