Include ouster_mapping in shared_library when BUILD_MAPPING is enabled

[czoido]

fix(mapping): include ouster_mapping in shared_library when BUILD_MAPPING is enabled

Hi!

While trying to bring the latest version to Conan Center Index (PR: conan-io/conan-center-index#28804) I found this problem while building the test_package:

When building with BUILD_SHARED_LIBRARY=ON and BUILD_MAPPING=ON, the ouster_mapping component is not properly included in the shared_library target. This causes linking errors because:

1. The ouster_mapping object files are not added to shared_library via target_sources()
2. The ouster_mapping target is not linked in ouster_library_common(), so its dependencies and include directories are not propagated

Here is the log failing:

Details

ouster_sdk/0.15.0 (test package): RUN: cmake --build "/Users/carlosz/Documents/developer/conan/conan-center-index/recipes/ouster_sdk/all/test_package/build/apple-clang-17-armv8-gnu17-release" -- -j14
ouster_sdk/0.15.0 (test package): Full command: . "/Users/carlosz/Documents/developer/conan/conan-center-index/recipes/ouster_sdk/all/test_package/build/apple-clang-17-armv8-gnu17-release/generators/conanbuild.sh" && cmake --build "/Users/carlosz/Documents/developer/conan/conan-center-index/recipes/ouster_sdk/all/test_package/build/apple-clang-17-armv8-gnu17-release" -- -j14
[ 50%] Building CXX object CMakeFiles/test_package.dir/test_package.cpp.o
[100%] Linking CXX executable test_package
ld: warning: ignoring duplicate libraries: '-lc++'
Undefined symbols for architecture arm64:
  "ouster::Preprocessor::Preprocessor(double, double, bool, int)", referenced from:
      _main in test_package.cpp.o
  "ouster::Preprocessor::Preprocess(std::__1::vector<Eigen::Matrix<double, 3, 1, 0, 3, 1>, std::__1::allocator<Eigen::Matrix<double, 3, 1, 0, 3, 1>>> const&, std::__1::vector<double, std::__1::allocator<double>> const&, Eigen::Matrix<double, 4, 4, 0, 4, 4> const&) const", referenced from:
      _main in test_package.cpp.o
ld: symbol(s) not found for architecture arm64
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [test_package] Error 1
make[1]: *** [CMakeFiles/test_package.dir/all] Error 2
make: *** [all] Error 2

This PR adds the missing integration of ouster_mapping into shared_library by:

1. Adding ouster_mapping object files to shared_library when the target exists (following the same pattern as other components)
2. Linking ouster_mapping and propagating its include directories in ouster_library_common() when BUILD_MAPPING is enabled

Here is the successful log after the fix:

Details

ouster_sdk/0.15.0 (test package): RUN: cmake --build "/Users/carlosz/Documents/developer/conan/conan-center-index/recipes/ouster_sdk/all/test_package/build/apple-clang-17-armv8-gnu17-release" -- -j14
ouster_sdk/0.15.0 (test package): Full command: . "/Users/carlosz/Documents/developer/conan/conan-center-index/recipes/ouster_sdk/all/test_package/build/apple-clang-17-armv8-gnu17-release/generators/conanbuild.sh" && cmake --build "/Users/carlosz/Documents/developer/conan/conan-center-index/recipes/ouster_sdk/all/test_package/build/apple-clang-17-armv8-gnu17-release" -- -j14
[ 50%] Building CXX object CMakeFiles/test_package.dir/test_package.cpp.o
[100%] Linking CXX executable test_package
ld: warning: ignoring duplicate libraries: '-lc++'
[100%] Built target test_package


======== Testing the package: Executing test ========
ouster_sdk/0.15.0 (test package): Running test()
ouster_sdk/0.15.0 (test package): RUN: ./test_package
ouster_sdk/0.15.0 (test package): Full command: . "/Users/carlosz/Documents/developer/conan/conan-center-index/recipes/ouster_sdk/all/test_package/build/apple-clang-17-armv8-gnu17-release/generators/conanrun.sh" && ./test_package
Successfully created a sensor::LidarScan object
Successfully created a osf::Writer object
Successfully created a sensor_utils::PcapReader object
Successfully created a SensorScanSource object
Successfully verified mapping component (SolverConfig, Preprocessor, dependencies)

This fix ensures that when BUILD_SHARED_LIBRARY=ON and BUILD_MAPPING=ON, all ouster_mapping symbols and its transitive dependencies are correctly included in the shared library, resolving undefined symbol errors at link time.