QUIC: handle EAGAIN properly on UDP sockets. Previously, the error was ignored leading to unnecessary retransmits. Now, unsent frames are returned into output queue, state is reset, and timer is started for the next send attempt.

# 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"