build: Fix undefined pthread references.

[orbea]

When building nghttp2 using --enable-asio-lib with slibtool (https://dev.midipix.org/cross/slibtool) it fails with undefined pthread references.

  CXXLD    libnghttp2_asio.la
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_io_service_pool.o: in function `boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:59: undefined reference to `pthread_create'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_io_service_pool.o: in function `boost::asio::detail::posix_thread::join()':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:42: undefined reference to `pthread_join'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_io_service_pool.o: in function `~posix_thread':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:35: undefined reference to `pthread_detach'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_io_service_pool.o: in function `boost::asio::detail::posix_thread::join()':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:42: undefined reference to `pthread_join'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_io_service_pool.o: in function `~posix_thread':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:35: undefined reference to `pthread_detach'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_io_service_pool.o: in function `posix_event':
/usr/include/boost/asio/detail/impl/posix_event.ipp:42: undefined reference to `pthread_condattr_setclock'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_io_service_pool.o: in function `thread<(lambda at /usr/bin/../lib64/gcc/x86_64-slackware-linux/10.2.0/../../../../include/c++/10.2.0/future:1671:27), void>':
/usr/bin/../lib64/gcc/x86_64-slackware-linux/10.2.0/../../../../include/c++/10.2.0/thread:149: undefined reference to `pthread_create'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_server.o: in function `~posix_thread':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:35: undefined reference to `pthread_detach'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_server.o: in function `boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:59: undefined reference to `pthread_create'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_server.o: in function `~posix_thread':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:35: undefined reference to `pthread_detach'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_server.o: in function `boost::asio::detail::posix_thread::join()':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:42: undefined reference to `pthread_join'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_server.o: in function `~posix_thread':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:35: undefined reference to `pthread_detach'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_server.o: in function `boost::asio::detail::posix_thread::join()':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:42: undefined reference to `pthread_join'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_server.o: in function `~posix_thread':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:35: undefined reference to `pthread_detach'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_client_session_impl.o: in function `boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:59: undefined reference to `pthread_create'
/usr/bin/ld: .libs/libnghttp2_asio_la-asio_client_session_impl.o: in function `~posix_thread':
/usr/include/boost/asio/detail/impl/posix_thread.ipp:35: undefined reference to `pthread_detach'
clang-11: error: linker command failed with exit code 1 (use -v to see invocation)
rlibtool: exec error upon slbt_exec_link_create_library(), line 1446: (see child process error messages).
rlibtool: < returned to > slbt_exec_link(), line 1843.
make[2]: *** [Makefile:1401: libnghttp2_asio.la] Error 2

This doesn't happen with GNU libtool because it silently filters out -no-undefined while slibtool does not which is set in lib/Makefile.am.

Additionally the existing pthread checks in configure.ac don't seem to work as m4/ax_pthread.m4 does and does not actually seem to be needed?

Also see this downstream issue: https://bugs.gentoo.org/776973

[orbea]

For reference NetworkManager and vapoursynth had similar issues which are now fixed.

See:

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/commit/3affccf29b53976a0cef5ea662f913d4913d44c8
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/804

vapoursynth/vapoursynth@93cf126
vapoursynth/vapoursynth#650

[Polynomial-C]

Any news here? What's holding this PR from being merged?

[voyageur]

Can we get this in? Anything blocking it? No conflicts and tests pass. It would avoid us not to carry that patch downstream and update it with autoconf changes

[tatsuhiro-t]

Sorry for late reply. libnghttp2_asio has been deprecated and will not get any update, and will be removed in the future release. Please consider remove the libnghttp2_asio package or provide this patch until it get removed.

[atari83]

😔 Could we find a maintainer for nghttp2_asio code ? It'd be a waste if we leave the code in this state.