Steps to reproduce the issue

$ apt-get install libboost1.71-all-dev
$ spack install -v range-v3 %gcc@:9 +examples cxxstd=14 ^boost@1.65.0
...

-- Found Boost: /usr/lib/x86_64-linux-gnu/cmake/Boost-1.71.0/BoostConfig.cmake (found suitable version "1.71.0", minimum required is "1.59.0") found components: date_time program_options 

Information on your system

• Spack: 0.16.0-102-623caf85a9
• Python: 3.8.6
• Platform: linux-ubuntu20.04-zen2
• Concretizer: clingo

Following https://cmake.org/cmake/help/latest/module/FindBoost.html#boost-cmake I've tried to fix this by adding this to boost/package.py:

    def setup_dependent_build_environment(self, env, dependent_spec):
        if '^cmake' in dependent_spec and '^boost@:1.69' in dependent_spec:
            env.set('Boost_NO_BOOST_CMAKE', 'ON')

but this does not work, you really need to specify cmake -DBoost_NO_BOOST_CMAKE=ON on the command line, which is currently awkward from the parent package.