compile fails under ubuntu noble if you include proj.h

[captain-igloo]

The following fails to compile under ubuntu noble. The error is error: conflicting declaration 'using PJ_CONTEXT = struct projCtx_t'. Is this a problem with mapnik or with the ubuntu package?

#include <proj.h>
#include <mapnik/map.hpp>

int main() {
    return 0;
}

$ git clone https://github.com/captain-igloo/mapnik-bug.git

$ cd mapnik-bug

$ docker build -t noble  -f Dockerfile  .

$ docker run noble g++ main.cpp

In file included from /usr/include/mapnik/proj_transform.hpp:29,
                 from /usr/include/mapnik/map.hpp:36,
                 from main.cpp:2:
/usr/include/mapnik/projection.hpp:46:7: error: conflicting declaration 'using PJ_CONTEXT = struct projCtx_t'
   46 | using PJ_CONTEXT = struct projCtx_t;
      |       ^~~~~~~~~~
In file included from main.cpp:1:
/usr/include/proj.h:387:23: note: previous declaration as 'typedef struct pj_ctx PJ_CONTEXT'
  387 | typedef struct pj_ctx PJ_CONTEXT;

[artemp]

@captain-igloo quick fix

g++ -DPROJ_VERSION=90301 main.cpp 

You can get compile/link flags using mapnik-config e.g

mapnik-config --defines 

-DMAPNIK_MEMORY_MAPPED_FILE -DMAPNIK_HAS_DLCFN -DBIGINT -DBOOST_REGEX_HAS_ICU -DHAVE_JPEG -DMAPNIK_USE_PROJ -DPROJ_VERSION=90301 -DHAVE_PNG -DHAVE_WEBP -DHAVE_TIFF -DLINUX -DMAPNIK_THREADSAFE -DBOOST_SPIRIT_NO_PREDEFINED_TERMINALS=1 -DBOOST_PHOENIX_NO_PREDEFINED_TERMINALS=1 -DBOOST_PHOENIX_STL_TUPLE_H_ -DBOOST_SPIRIT_USE_PHOENIX_V3=1 -DNDEBUG -DHAVE_CAIRO -DGRID_RENDERER -DHAVE_LIBXML2

[captain-igloo]

Thank you