Build from source failure on undeclared identifier _POSIX_SEM_VALUE_MAX

[willwray]

(Reporting here rather than cppyy repo because this issue is specific to the build here.)

I'm attempting to follow the instructions for building from source

Start with the cppyy-cling package (cppyy-backend repo, subdirectory “cling”), which requires source to be pulled in from upstream, and thus takes a few extra steps:

$ git clone https://github.com/wlav/cppyy-backend.git
$ cd cppyy-backend/cling
$ python setup.py egg_info
$ python create_src_directory.py
$ python -m pip install . --upgrade

This fails for me on two different systems and three compilers
Ubuntu (with clang16 or gcc11.4) and Fedora36 with gcc12.2

(Should I retry with other or older compilers?)

The SEM_VALUE_MAX error starts with commit 00c7bed "upgrade Cling from upstream (28.04)"
(before that commit there's another blocking error - a compile fail on a const qualifier).

Ubuntu 22.04.3 GCC11.4

      [ 97%] Generating G__ThreadLegacy.cxx, ../../lib/libThreadLegacy.rootmap
      In file included from input_line_8:16:
      In file included from /Data/home/will/repos/cppyy-backend/cling/builddir/include/ROOT/TReentrantRWLock.hxx:21:
      In file included from /usr/include/c++/11/condition_variable:47:
      In file included from /usr/include/c++/11/stop_token:37:
      In file included from /usr/include/c++/11/semaphore:35:
      /usr/include/c++/11/bits/semaphore_base.h:62:41: error: use of undeclared identifier '_POSIX_SEM_VALUE_MAX'; did you mean '_SC_SEM_VALUE_MAX'?
          static constexpr ptrdiff_t _S_max = _POSIX_SEM_VALUE_MAX;
                                              ^
      /usr/include/x86_64-linux-gnu/bits/confname.h:140:5: note: '_SC_SEM_VALUE_MAX' declared here
          _SC_SEM_VALUE_MAX,
          ^
      Error: /Data/home/will/repos/cppyy-backend/cling/builddir/core/rootcling_stage1/src/rootcling_stage1: compilation failure (/Data/home/will/repos/cppyy-backend/cling/builddir/lib/libThreadLegacyde1d7a8d17_dictUmbrella.h)
      gmake[2]: *** [core/thread/CMakeFiles/G__ThreadLegacy.dir/build.make:106: core/thread/G__ThreadLegacy.cxx] Error 1
      gmake[1]: *** [CMakeFiles/Makefile2:28486: core/thread/CMakeFiles/G__ThreadLegacy.dir/all] Error 2
      gmake[1]: *** Waiting for unfinished jobs....
      [ 97%] Built target Cling
      gmake: *** [Makefile:156: all] Error 2
      error: Failed to build cppyy-cling

Fedora36 GCC12.2

  [ 97%] Generating G__ThreadLegacy.cxx, ../../lib/libThreadLegacy.rootmap
  In file included from input_line_8:16:
  In file included from /home/will/repos/cppyy-backend/cling/builddir/include/ROOT/TReentrantRWLock.hxx:21:
  In file included from /usr/lib/gcc/x86_64-redhat-linux/12/../../../../include/c++/12/condition_variable:46:
  In file included from /usr/lib/gcc/x86_64-redhat-linux/12/../../../../include/c++/12/stop_token:37:
  In file included from /usr/lib/gcc/x86_64-redhat-linux/12/../../../../include/c++/12/semaphore:35:
  /usr/lib/gcc/x86_64-redhat-linux/12/../../../../include/c++/12/bits/semaphore_base.h:59:41: error: use of undeclared identifier '_POSIX_SEM_VALUE_MAX'; did you mean '_SC_SEM_VALUE_MAX'?
      static constexpr ptrdiff_t _S_max = _POSIX_SEM_VALUE_MAX;
                                          ^
  /usr/include/bits/confname.h:140:5: note: '_SC_SEM_VALUE_MAX' declared here
      _SC_SEM_VALUE_MAX,
      ^
...

[wlav]

Related: #12

[wlav]

Workaround in repo as detailed in #12 .