Merge selected bug fixes from trunk:
* Fixed a compile error on some versions of g++ due to anonymous enums.
Fixes #4883.
* Fixed a bug in asio::streambuf where the consume() function did not
always update the internal buffer pointers correctly. The problem may
occur when the asio::streambuf is filled with data using the standard
C++ member functions such as sputn(). (Note: the problem does not
manifest when the streambuf is populated by the Asio free functions
read(), async_read(), read_until() or async_read_until().)
* EV_ONESHOT seems to cause problems on some versions of Mac OS X, with
the io_service destructor getting stuck inside the close() system
call. Use EV_CLEAR instead. Fixes #5021.
* Fixed a bug on kqueue-based platforms, where reactor read operations
that return false from their perform() function are not correctly
re-registered with kqueue.
* Fixed the linger socket option on non-Windows platforms.
* Fixed function name in comment for asio::placeholders::iterator.
[SVN r69680]
Christopher Kohlhoff