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

[ylatuya at gmail dot com]

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



--- Comment #1 from Andoni <ylatuya at gmail dot com> 2013-05-08 13:40:46 UTC 
---

Created attachment 30056

  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30056

Fix libstdc threads for mingw