Fix double declared function pthread_self


git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@6528 4407c894-4637-0410-b4f5-ada5f102cad1
winerror.h: Added some missing error codes.

git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@6529 4407c894-4637-0410-b4f5-ada5f102cad1