Supported poll() for socket event notification. --event-poll can
take value "poll". Fixed the bug that timeout for
SocketCore::isReadable()/isWritable() is ignored when epoll is
used.
* src/OptionHandlerFactory.cc
* src/a2io.h
* src/prefs.h
* src/SocketCore.h
* src/Makefile.am
* src/main.cc
* src/PollEventPoll.h
* src/SocketCore.cc
* src/DownloadEngineFactory.cc
* src/PollEventPoll.cc
* src/prefs.cc
* configure.ac
Tatsuhiro Tsujikawa