dev-libs/boost/files/boost-1.90.0-msm-std.patch

   1 The msm-unit-tests-cxxstd20 testsuite sets <cxxstd>20, but unfortunately
   2 this setting is prepended relative to the ebuild's setting:
   3
   4   x86_64-pc-linux-gnu-g++ -std=c++20 -fvisibility-inlines-hidden
   5   -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
   6   -pipe -O -std=c++17
   7
   8 which causes an expected build error:
   9
  10   In file included from Back11OrthogonalDeferred3WithPuml.cpp:15:
  11   boost/msm/front/puml/puml.hpp: In function 'constexpr auto boost::msm::front::puml::detail::parse_guard_simple(Func)':
  12   boost/msm/front/puml/puml.hpp:511:25: error: lambda-expression in unevaluated context only available with
  13   '-std=c++20' or '-std=gnu++20' [-Wtemplate-body]
  14
  15 Setting -std=c++20 globally for the gcc toolchain lets all tests pass.
  16
  17 --- boost_1_90_0/libs/msm/test/Jamfile.v2~
  18 +++ boost_1_90_0/libs/msm/test/Jamfile.v2
  19 @@ -19,7 +19,7 @@ project
  20      requirements
  21         <library>/boost/msm//boost_msm
  22         <include>.
  23 -       <toolset>gcc:<cxxflags>"-ftemplate-depth-300 -g0"
  24 +       <toolset>gcc:<cxxflags>"-ftemplate-depth-300 -g0 -std=c++20"
  25         <toolset>darwin:<cxxflags>"-ftemplate-depth-300 -g0"
  26         <toolset>intel:<cxxflags>"-g0"
  27         <toolset>gcc:<optimization>off