Fix/bjam leaking cxx14

[tinko92]

This PR aims to solve #1460 . The cxx14 requirements are moved from build.jam to the respective buildable targets. Because I lack deeper insight into the B2 conventions in boost, I copied this pattern from boostorg/gil. In addition this PR also sets the target C++ version via 14 for all buildable targets. This fixes the tests not building on my machine without adding a cxx version, probably due to https://github.com/boostorg/boost/blob/2813c94a3eefd1adbf623703f9c4d8e818f5398f/Jamroot#L256 . It's two commits to separate out the change to extensions for release picking.

The added include of array in code.hpp is due to this breaking the CI header target, I suspect because GCC otherwise defaults to a higher C++ version where the include from comes indirectly through some other include chain but of course it should be explicit where it's used anyway so this was an oversight in my original work.

[tinko92]

This doesn't show the problematic behaviour mentioned in the issue on my platform, full output until first copy:

➜  boost git:(develop) ✗ ./b2 --with-headers install \
  --prefix=/tmp/boost-install-test \
  --build-dir=/tmp/boost-build-test
Performing configuration checks

    - default address-model    : 64-bit [1]
    - default architecture     : arm [1]
    - symlinks supported       : yes
error: No best alternative for /Users/tinko/dev/boost/libs/histogram/install-libraries-shared with <abi>aapcs <address-model>64 <architecture>arm <asynch-exceptions>off <binary-format>mach-o <boost.beast.allow-deprecated>on <boost.beast.separate-compilation>on <boost.cobalt.executor>any_io_executor <boost.cobalt.pmr>std <context-impl>fcontext <coverage>off <cxxstd-dialect>iso <cxxstd>11 <debug-symbols>off <exception-handling>on <extern-c-nothrow>off <inlining>full <known-warnings>hide <link>shared <optimization>speed <os>MACOSX <pch>on <preserve-test-targets>on <profiling>off <python-debugging>off <python>3.14 <relevant>target-os <rtti>on <runtime-debugging>off <runtime-link>shared <stdlib>native <strip>off <target-os>darwin <testing.execute>on <threadapi>pthread <threading>multi <toolset-clang:platform>darwin <toolset-clang:version>21 <toolset>clang <variant>release <vectorize>off <visibility>hidden <warnings-as-errors>off <warnings>on <x-deduced-platform>arm_64
    no match: <local-visibility>hidden
    no match: <local-visibility>hidden <target-os>cygwin
error: No best alternative for /Users/tinko/dev/boost/libs/histogram/install-libraries-shared with <abi>aapcs <address-model>64 <architecture>arm <asynch-exceptions>off <binary-format>mach-o <boost.beast.allow-deprecated>on <boost.beast.separate-compilation>on <boost.cobalt.executor>any_io_executor <boost.cobalt.pmr>std <context-impl>fcontext <coverage>off <cxxstd-dialect>iso <cxxstd>11 <debug-symbols>off <exception-handling>on <extern-c-nothrow>off <inlining>full <known-warnings>hide <link>static <optimization>speed <os>MACOSX <pch>on <preserve-test-targets>on <profiling>off <python-debugging>off <python>3.14 <relevant>target-os <rtti>on <runtime-debugging>off <runtime-link>shared <stdlib>native <strip>off <target-os>darwin <testing.execute>on <threadapi>pthread <threading>multi <toolset-clang:platform>darwin <toolset-clang:version>21 <toolset>clang <variant>release <vectorize>off <visibility>hidden <warnings-as-errors>off <warnings>on <x-deduced-platform>arm_64
    no match: <local-visibility>hidden
    no match: <local-visibility>hidden <target-os>cygwin

[1] clang-21

Component configuration:

    - atomic                   : not building
    - charconv                 : not building
    - chrono                   : not building
    - cobalt                   : not building
    - container                : not building
    - context                  : not building
    - contract                 : not building
    - coroutine                : not building
    - date_time                : not building
    - exception                : not building
    - fiber                    : not building
    - filesystem               : not building
    - graph                    : not building
    - graph_parallel           : not building
    - headers                  : building
    - iostreams                : not building
    - json                     : not building
    - locale                   : not building
    - log                      : not building
    - math                     : not building
    - mpi                      : not building
    - nowide                   : not building
    - process                  : not building
    - program_options          : not building
    - python                   : not building
    - random                   : not building
    - regex                    : not building
    - serialization            : not building
    - stacktrace               : not building
    - system                   : not building
    - test                     : not building
    - thread                   : not building
    - timer                    : not building
    - type_erasure             : not building
    - url                      : not building
    - wave                     : not building

...found 34555 targets...
...updating 18061 targets...
common.copy /tmp/boost-install-test/include/boost/align.hpp

[Copilot]

Pull request overview

This PR updates Boost.Build (B2) configuration for Boost.Geometry to avoid running C++14 feature checks at the global project level (which affected unrelated builds like --with-headers install), and instead applies the C++14 requirements only to buildable targets. It also ensures buildable targets request C++14 explicitly via <cxxstd>14, and fixes an implicit header dependency by adding a missing standard include.

Changes:

• Removed global cxx14_constexpr / cxx14_return_type_deduction requirements from build.jam, and moved include path propagation to the boost_geometry alias.
• Added <cxxstd>14 plus the C++14 feature checks to the buildable target projects (tests, examples, index, extensions, doc examples).
• Added a missing #include <array> where std::array is used.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
build.jam	Removes global C++14 feature checks and moves <include>include to the boost_geometry alias usage-requirements to avoid impacting unrelated builds.
test/Jamfile	Applies <cxxstd>14 and C++14 feature checks to the test project only.
example/Jamfile	Applies <cxxstd>14 and C++14 feature checks to the examples project only.
doc/src/examples/Jamfile	Applies <cxxstd>14 and C++14 feature checks to the doc examples project only.
index/Jamfile	Applies <cxxstd>14 and C++14 feature checks to the index project only.
extensions/Jamfile	Applies <cxxstd>14 and C++14 feature checks to the extensions project only.
include/boost/geometry/srs/projections/code.hpp	Adds explicit <array> include required by std::array usage.

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[barendgehrels]

Thanks! Looks good to me. I won't test locally (never use b2 anymore).
Also good you have the commit for extensions separately

[vissarion]

LGTM!