QUICStreamVCAdapter.cc:27: undefined reference to `VIO::VIO()'

[bneradt]

Clang 13.0.1 currently presents a few warnings for our master branch. These are addressed in #8685. However, after these compiler warnings are addressed, the following linker error is produced:

  CXXLD    traffic_server/traffic_server
/usr/bin/ld: ../iocore/net/quic/libquic.a(QUICStreamVCAdapter.o): in function `QUICStreamVCAdapter':
/var/tmp/trafficserver/iocore/net/quic/QUICStreamVCAdapter.cc:27: undefined reference to `VIO::VIO()'
/usr/bin/ld: /var/tmp/trafficserver/iocore/net/quic/QUICStreamVCAdapter.cc:27: undefined reference to `VIO::VIO()'
clang-13: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [Makefile:2142: traffic_server/traffic_server] Error 1
make[2]: Leaving directory '/var/tmp/trafficserver/src'
make[1]: *** [Makefile:2813: all-recursive] Error 1
make[1]: Leaving directory '/var/tmp/trafficserver/src'
make: *** [Makefile:874: all-recursive] Error 1

This can be reproduced with the CI's fedora:36 Docker image like so:

docker pull controller.trafficserver.org/ats/fedora:36
docker run -it controller.trafficserver.org/ats/fedora:36 /bin/bash
cd /var/tmp
git clone https://github.com/apache/trafficserver.git
cd trafficserver

# Apply the patch from #8685.

export CC="clang"
export CXX="clang++"
export CXXFLAGS="-Qunused-arguments"
export WITH_LIBCPLUSPLUS="yes"

autoreconf -fiv
./configure --with-openssl=/opt/openssl-quic --enable-experimental-plugins --enable-example-plugins --prefix=/tmp/ats/ --enable-werror --enable-debug --enable-wccp --enable-luajit --enable-ccache
make -j4 V=1 Q=

[bneradt]

Looks like this is a library ordering issue. libquic.a requires VIO::VIO() which is provided by iocore/eventsystem/libinkevent.a, but that appears earlier in the link command. If I add libinkevent.a after libquic.a, the command succeeds.