[rebase]: don't link stdc++/c++

Author: alexcrichton

src/etc/mklldeps.py

@@ -80,6 +80,9 @@ def run(args):
     assert('stdlib=libc++' not in out)
     f.write("#[link(name = \"stdc++\", kind = \"static\")]\n")
 else:
+    # Note that we use `cfg_attr` here because on MSVC the C++ standard library
+    # is not c++ or stdc++, but rather the linker takes care of linking the
+    # right standard library.
     if 'stdlib=libc++' in out:
         f.write("#[cfg_attr(not(target_env = \"msvc\"), link(name = \"c++\"))]\n")
     else: