[pkg-config] Provide a single package-config `.pc` file for all pcl libraries

[Rapyuta-ConnorPerrin]

pkg-config with pcl needs to be informed of each individual library. It's quite bothersome

Expected behavior

pkg-config --cflags pcl should return the cflags for all PCL libraries

Current Behavior

Need to call pkg-config --cflags pcl_common and so on

Additional context

Every module's CMakeLists.txt creates a pkg-config. This can be done by creating a fake module which depends on all built modules and then generates a pkg-config file

[mvieth]

Could you describe your use case a bit more? Why are you calling pkg-config/ how are you using the cflags? Is it not possible to use cmake in your situation?

[kunaltyagi]

CMake isn't possible. So far, even integration with compile_commands.json looks to be quite difficult.

An example of the use-case is: https://github.com/rapyuta-robotics/jupyter_ros_utils/blob/main/cpp/notebooks/pcl-1.10.ipynb

(using C++ in Jupyter via cling interpreter)