Log Message:
libev: updated to 4.25

4.25:
- INCOMPATIBLE CHANGE: EV_THROW was renamed to EV_NOEXCEPT
  (EV_THROW sitll provided) and now uses noexcept on C++11 or newer.
- move the darwin select workaround highe rin ev.c, as newer versions of
  darwin managed to break their broken select even more.
- ANDROID => __ANDROID__ (reported by enh@google.com).
- disable epoll_create1 on android because it has broken header files
  and google is unwilling to fix them (reported by enh@google.com).
- avoid a minor compilation warning on win32.
- c++: remove deprecated dynamic throw() specifications.
- c++: improve the (unsupported) bad_loop exception class.
- backport perl ev_periodic example to C, untested.
- update libecb, biggets change is to include a memory fence
  in ECB_MEMORY_FENCE_RELEASE on x86/amd64.
- minor autoconf/automake modernisation.