[Bug libstdc++/57212] Don't use pe-coff weak support with mingw

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57212

--- Comment #6 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-05-08 
15:16:09 UTC ---
Remember to regenerate Makefile.in.