http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55521
--- Comment #8 from Jack Howarth <howarth at nitro dot med.uc.edu> 2012-12-01 01:50:37 UTC --- Note that fixing this by replacing mach_override with interpose will require FSF gcc to be enhanced to provide the missing blocks support (which was developed after the GPLv3 transition and will thus have to be coded from scratch).
