build: Require C11

[jtojnar]

Since c95738b, the compiler will complain “ISO C99 doesn't support unnamed structs/unions”.

Let’s switch to C11 standard, which support that feature.

[mikedld]

@jtojnar could you share some more details please? Which compiler/version are we talking about? Is this when building libutp itself (which uses C++, not C internally) or when building some other project that's using it (which one? does it use C or C++?)?

[jtojnar]

It is when building libutp standalone from fda9f4b, using GCC 12.2.0.

Here is the full log:

cmake flags: -DCMAKE_FIND_USE_SYSTEM_PACKAGE_REGISTRY=OFF -DCMAKE_FIND_USE_PACKAGE_REGISTRY=OFF -DCMAKE_EXPORT_NO_PACKAGE_REGISTRY=ON -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTING=OFF -DCMAKE_INSTALL_LOCALEDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/share/locale -DCMAKE_INSTALL_LIBEXECDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/libexec -DCMAKE_INSTALL_LIBDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/lib -DCMAKE_INSTALL_DOCDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/share/doc/libutp -DCMAKE_INSTALL_INFODIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/share/info -DCMAKE_INSTALL_MANDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/share/man -DCMAKE_INSTALL_OLDINCLUDEDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/include -DCMAKE_INSTALL_INCLUDEDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/include -DCMAKE_INSTALL_SBINDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/sbin -DCMAKE_INSTALL_BINDIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/bin -DCMAKE_INSTALL_NAME_DIR=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13/lib -DCMAKE_POLICY_DEFAULT_CMP0025=NEW -DCMAKE_OSX_SYSROOT= -DCMAKE_FIND_FRAMEWORK=LAST -DCMAKE_STRIP=/nix/store/bfbp3ypd9nm3fapz634gvvs738blrl0y-gcc-wrapper-12.2.0/bin/strip -DCMAKE_RANLIB=/nix/store/bfbp3ypd9nm3fapz634gvvs738blrl0y-gcc-wrapper-12.2.0/bin/ranlib -DCMAKE_AR=/nix/store/bfbp3ypd9nm3fapz634gvvs738blrl0y-gcc-wrapper-12.2.0/bin/ar -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DCMAKE_INSTALL_PREFIX=/nix/store/4dm9zk1m6v9hpz4yg10m2gm7qi68s36l-libutp-unstable-2023-02-13  
-- The C compiler identification is GNU 12.2.0
-- The CXX compiler identification is GNU 12.2.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /nix/store/bfbp3ypd9nm3fapz634gvvs738blrl0y-gcc-wrapper-12.2.0/bin/gcc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /nix/store/bfbp3ypd9nm3fapz634gvvs738blrl0y-gcc-wrapper-12.2.0/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
CMake Warning:
  Manually-specified variables were not used by the project:

    BUILD_TESTING
    CMAKE_EXPORT_NO_PACKAGE_REGISTRY
    CMAKE_FIND_USE_PACKAGE_REGISTRY
    CMAKE_FIND_USE_SYSTEM_PACKAGE_REGISTRY
    CMAKE_POLICY_DEFAULT_CMP0025


-- Build files have been written to: /build/source/build
cmake: enabled parallel building
building
build flags: -j8 SHELL=/nix/store/5ynbf6wszmggr0abwifdagrixgnya5vy-bash-5.2-p15/bin/bash
[ 11%] Building CXX object CMakeFiles/libutp.dir/utp_callbacks.cpp.o
[ 22%] Building CXX object CMakeFiles/libutp.dir/utp_internal.cpp.o
[ 33%] Building CXX object CMakeFiles/libutp.dir/utp_api.cpp.o
[ 44%] Building CXX object CMakeFiles/libutp.dir/utp_hash.cpp.o
[ 55%] Building CXX object CMakeFiles/libutp.dir/utp_packedsockaddr.cpp.o
[ 66%] Building CXX object CMakeFiles/libutp.dir/utp_utils.cpp.o
[ 77%] Linking CXX static library libutp.a
[ 77%] Built target libutp
[ 88%] Building C object CMakeFiles/ucat.dir/ucat.c.o
In file included from /build/source/ucat.c:46:
/build/source/include/libutp/utp.h:113:10: error: ISO C99 doesn't support unnamed structs/unions [8;;https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wpedantic-Werror=pedantic8;;]
  113 |         };
      |          ^
/build/source/include/libutp/utp.h:118:10: error: ISO C99 doesn't support unnamed structs/unions [8;;https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wpedantic-Werror=pedantic8;;]
  118 |         };
      |          ^
cc1: all warnings being treated as errors
make[2]: *** [CMakeFiles/ucat.dir/build.make:76: CMakeFiles/ucat.dir/ucat.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:111: CMakeFiles/ucat.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

[mikedld]

Could you also fixup the readme, based on bittorrent#100?

FYI I appreciate you opening this PR, but the main use-case for this repository and this non-main branch is to be built as a submodule in the main Transmission repo (which doesn't build/need ucat, just the library), not standalone. We don't intend to provide support for libutp here (or at least it certainly wasn't the original intention), so publishing a package using this repo and this branch, and built as static, is... somewhat odd IMHO, although of course always your choice e.g. if some other package(s) will make good use of it too.

Still, kind of nice to have the standalone build passing.

[jtojnar]

Done.

We are using the standalone libutp as a dependency for Transmission (and few other clients based on libtransmission). Currently updating the package to 4.0.