http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54806
--- Comment #20 from Jack Howarth <howarth at nitro dot med.uc.edu> 2012-10-06 21:06:45 UTC --- Also, you might want to look at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39888 which shows the thought process and issues that arose during the libgcc_ext development.