This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 112e. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.
[Adopted at the February, 2016 meeting.]
The current wording does not appear to ban a pure-specifier from a friend declaration.
Proposed resolution (February, 2016):
Change 11.4 [class.mem] paragraph 6 as follows:
...A pure-specifier shall be used only in the declaration of a virtual function (11.7.3 [class.virtual]) .