Installing v6.0.0-rc.1 does not populate /usr/local/include #7135
Description
Issue
I have a downstream project using libosrm, relying on pkg-config to link to the relevant header files. Those have historically always been installed in /usr/local/include/osrm.
But when following the usual build + install steps with the latest tag v6.0.0-rc.1, no folder /usr/local/include/osrm is created.
This is what I used to get after build + install with a previous dev version (master at d259848):
$ ls /usr/local/include/osrm/
approach.hpp contractor.hpp datasets.hpp exception.hpp json_container.hpp osrm.hpp route_parameters.hpp table_parameters.hpp
bearing.hpp coordinate.hpp engine extractor match_parameters.hpp partitioner status.hpp tile_parameters.hpp
contractor customizer_config.hpp engine_config.hpp extractor_config.hpp nearest_parameters.hpp partitioner_config.hpp storage trip_parameters.hpp
contractor_config.hpp customizer.hpp error_codes.hpp extractor.hpp osrm_fwd.hpp partitioner.hpp storage_config.hpp util
Link to a downstream CI check containing all OSRM build and install steps, then failing to find a libosrm header file: https://github.com/VROOM-Project/vroom/actions/runs/13973127966/job/39119910020?pr=1235
Specifications
Build/install done on Ubuntu 24.04 with gcc.