Updating package for devel/libev from 3.7nb1 to 3.8
- bumping API/ABI-depends, because upstream change says nothing about
  ABI/API incompatible change

Upstream changes:
3.8  Sun Aug  9 14:30:45 CEST 2009
- incompatible change: do not necessarily reset signal handler
          to SIG_DFL when a sighandler is stopped.
        - ev_default_destroy did not properly free or zero some members,
          potentially causing crashes and memory corruption on repated
          ev_default_destroy/ev_default_loop calls.
- take advantage of signalfd on GNU/Linux systems.
- document that the signal mask might be in an unspecified
          state when using libev's signal handling.
        - take advantage of some GNU/Linux calls to set cloexec/nonblock
          on fd creation, to avoid race conditions.

(sno)