Merge of r5017: fixed null dereference with resolver and poll. Events: fixed null pointer dereference with resolver and poll. A POLLERR signalled by poll() without POLLIN/POLLOUT, as seen on Linux, would generate both read and write events, but there's no write event handler for resolver events. A fix is to only call event handler of an active event.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


# aCC: HP ANSI C++ B3910B A.03.55.02

# C89 mode

CFLAGS="$CFLAGS -Ae"
CC_TEST_FLAGS="-Ae"

PCRE_OPT="$PCRE_OPT -Ae"
ZLIB_OPT="$ZLIB_OPT -Ae"
MD5_OPT="$MD5_OPT -Ae"