Previously both the static version of libc++ and the import library for the DLL had the same name, 'c++.lib'. This patch renames the static library on Windows to be `libc++.lib` so it no longer conflicts. This naming convention is consistent with other windows libraries. git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@300817 91177308-0d34-0410-b5e6-96231b3b80d8