Change return type of CreateSymbolicLink to BOOLEAN as described in
http://msdn.microsoft.com/en-us/library/aa363866%28VS.85%29.aspx



git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@2834 4407c894-4637-0410-b4f5-ada5f102cad1