I've already submitted a bug report about this issue with GDB, but I've also found it's happening with building binutils itself for x86_64-w64-mingw32 (native). The bug report is here: http://sourceware.org/bugzilla/show_bug.cgi?id=15067
Additionally, when building native GCC 4.8.0 from SVN, ld starts freeing invalid pointers like it's going out of style, failing almost every link, as far as I can tell.