libpcl @1.7.2: error: static_assert failed "Allocator::value_type must be same type as value_type"

[tiktaktok (Mathieu Clement)]

When trying to build libpcl, the following error appears in the log file:

info:build In file included from /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_gis_libpcl/libpcl/work/pcl-1.7.2/kdtree/include/pcl/kdtree/flann.h:50:
:info:build In file included from /opt/local/include/flann/flann.hpp:41:
:info:build In file included from /opt/local/include/flann/util/matrix.h:35:
:info:build In file included from /opt/local/include/flann/util/serialization.h:5:
:info:build /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/map:820:5: error: static_assert failed "Allocator::value_type must be same type as value_type"
:info:build     static_assert((is_same<typename allocator_type::value_type, value_type>::value),
:info:build     ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:info:build /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__config:729:36: note: expanded from macro 'static_assert'
:info:build #   define static_assert(__b, __m) _Static_assert(__b, __m)
:info:build                                    ^              ~~~
:info:build /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_gis_libpcl/libpcl/work/pcl-1.7.2/features/include/pcl/features/pfh.h:211:131: note: in instantiation of template class 'std::__1::map<std::__1::pair<int, int>, Eigen::Matrix<float, 4, 1, 0, 4, 1>, std::__1::less<std::__1::pair<int, int> >, Eigen::aligned_allocator<Eigen::Matrix<float, 4, 1, 0, 4, 1> > >' requested here
:info:build       std::map<std::pair<int, int>, Eigen::Vector4f, std::less<std::pair<int, int> >, Eigen::aligned_allocator<Eigen::Vector4f> > feature_map_;
:info:build                                         

[tiktaktok (Mathieu Clement)]

I think it would be useful to mention that I am using the newly released Mac OS High Sierra, with XCode 9.0.

[ryandesign (Ryan Carsten Schmidt)]

Patch provided in #56430.