CMakeLists: fix import of external jansson and utf8cpp

[gerion0]

No description provided.

[biodranik]

How did it work on other systems without explicit PkgConfig specification? Will it continue to work? Why it doesn't find the library without explicit PkgConfig?

CC @Ferenc-

[gerion0]

Normally, jansson is vendored as a 3party and configured with CMake:
https://github.com/organicmaps/organicmaps/blob/master/3party/CMakeLists.txt#L35

This will continue to work. A jansson installation of a distribution normally contains (just) a pkgconfig file (it's pretty common). See for example the debian package: https://packages.debian.org/bookworm/amd64/libjansson-dev/filelist

Why it doesn't find the library without explicit PkgConfig?

Appearently, CMake's find_package does not search for pkgconfig files. It needs the FindPkgConfig module for that: https://cmake.org/cmake/help/latest/module/FindPkgConfig.html

[biodranik]

Does it mean that on Debian/Ubuntu the current master works with PkgConfig for utf8 even without explicitly writing it in cmake? If yes, why? Could it be that cmake detects some pkgconfig vars/files/configs on Debian/Ubuntu, but doesn't do it on Gentoo for some reason? Maybe some env vars are missing?

cmake has --trace parameter that may be helpful to discover issues with packages.

[gerion0]

Do you mean the test pipeline here? Does it build with or without WITH_SYSTEM_PROVIDED_3PARTY?

[Ferenc-]

How did it work on other systems without explicit PkgConfig specification?

It's not past tense, it is present. It is still working with WITH_SYSTEM_PROVIDED_3PARTY perfectly fine, if one installs the latest release of jansson on a system. The find_package is looking for janssonConfig.cmake first, and that is by default installed to /usr/local/lib/cmake/jansson/ if you install from source.

[Ferenc-]

Upstream jansson provides a pkgconfig file instead of a cmake file.

Just because your distro doesn't have a cmake file for jansson, that doesn't mean that upstream doesn't provide it. I believe there is evidence to the contrary.

[gerion0]

These are distros that don't provide a cmake file but a pkgconfig file:

• Gentoo (the ebuild does not delete a cmake file actively, version 2.14)
• Debian (stable, bookworm, v2.14, unstable, sid, v2.14
• Ubuntu (mantic, v2.14)
• Fedora 40 (v2.13, filelist)
• OpenSuse (v2.14, filelist not online accessible, one must extract the RPM)
• Arch Linux (filelist)

and that is by default installed to /usr/local/lib/cmake/jansson/ if you install from source.

I tried building myself with these commands (as recommended in the readme):

autoreconf -i
./configure
make
DESTDIR="$PWD/install" make install

I got these files:

./usr
./usr/local
./usr/local/lib
./usr/local/lib/libjansson.so.4.14.0
./usr/local/lib/libjansson.so.4
./usr/local/lib/libjansson.so
./usr/local/lib/libjansson.la
./usr/local/lib/libjansson.a
./usr/local/lib/pkgconfig
./usr/local/lib/pkgconfig/jansson.pc
./usr/local/include
./usr/local/include/jansson.h
./usr/local/include/jansson_config.h

There is a cmake folder within libjansson and it seems to be possible to build with cmake. I'm assuming in this case, it installs the cmake file, but no distro that I checked does that and it is not recommended by upstream.

[biodranik]

I do not understand why "build 3p from source" approach should be used if you can literally "build 3p of the necessary, usually most recent version from organic maps source" automatically.

Do we need a more flexible way to specify which libs should be taken from the system, and which libs should be built from OM source? Of course, I would prefer to keep things simple, and always build everything from OM repo. It helps to test 3ps that are used on mobiles and also on other desktop machines. And we can always use the bleeding edge versions of 3ps with the latest features and fixes. Without wasting time of maintainers to provide patches for each system.

[Ferenc-]

That's a respectable research you did on distro packages. I just don't immediately see why. My comment was merely about the commit message, which has a statement aboutupstream not providing a cmake file.
And by now hopefully we can all observe, that if you do a cmake -B build . && cd build && make && sudo make install in the jansson source dir, then you do get all the needed cmake files.

[Ferenc-]

I do not understand why "build 3p from source" approach should be used

I don't think it was even discussed which approach should or should not be used. From my side I was just pointing out one valid way of using systems, that many people and potential users do. Especially among those, who understand and appreciate the benefits of open source.

Do we need a more flexible way to specify which libs should be taken from the system, and which libs should be built from OM source?

I don't think so. I think the discussion is mainly about the nuances of how specifically jansson is made available on different systems.

[gerion0]

That's a respectable research you did on distro packages. I just don't immediately see why. My comment was merely about the commit message, which has a statement aboutupstream not providing a cmake file.

Ah, I understood it in a way that you meant the patch as a whole. I reformulated the commit message and hope it is better formulated now.

that if you do a cmake -B build . && cd build && make && sudo make install in the jansson source dir, then you do get all the needed cmake files.

Interestingly, this results in a compilation error for me (while an autotools build works).

I don't think so. I think the discussion is mainly about the nuances of how specifically jansson is made available on different systems.

I agree to that.