Proposed resolution:

Change [using.linkage] paragraph 2 from:

It is unspecified whether a name from the Standard C library declared with external linkage has either extern "C" or extern "C++" linkage.

to:

Whether a name from the Standard C library declared with external linkage has extern "C" or extern "C++" linkage is implementation defined. It is recommended that an implementation use extern "C++" linkage for this purpose.

The change specified in the proposed resolution below did not make it into the Standard. This change was accepted in principle at the London meeting, and the exact wording below was accepted at the Morristown meeting.