Can't compile as sub-dependency

Hello,

I'm not managing to compile my project, not sure it's abseil's fault.
My project depends on [s2geometry](https://github.com/google/s2geometry), which in turn depends on abseil.
s2geometry used to include their own version of abseil, but now that they made it [external](https://github.com/google/s2geometry/commit/d10e042b9316369c3eefa4c14774d35c8ddb66b1) I can't compile anymore.

Indeed in my CMakeLists.txt I added add_subdirectory(third-party/abseil) before add_subdirectory(third-party/s2geometry) but s2 complained that it couldn't find abslConfig.cmake so I used set(ABSL_ENABLE_INSTALL ON) to have it, but now I'm stuck on the following error:
CMake Error at build/third-party/abseil-cpp/abslConfig.cmake:32 (include):
[cmake] include could not find load file:
[cmake]
[cmake] [...]/build/third-party/abseil-cpp/abslTargets.cmake
[cmake] Call Stack (most recent call first):
[cmake] third-party/s2geometry/CMakeLists.txt:71 (find_package)

The targets don't seem to be installed when add_subdirectory(third-party/abseil) finishes, when s2 launches find_package(absl REQUIRED).
Which brings me to my question: is there a way to include abseil as a sub-dependency, or am I missing something here?

Best regards,
Paul