Install target generates a clean CMake package (+ Catkin dependency is now optional)

[blabdouze]

Install target now generate a clean CMake package :

• lib folder that contains the static library (debug and release)
• include folder that contains the *.h
• cmake folder that contains all the cmake related files (exported targets + version file)

This allow the package to be found by a find_package() call if you set serial_DIR var to the path of cmake folder.

# You can also specify the version if needed
find_package(serial REQUIRED)

# Don't need to specify serial include directories as the target already defines them.  
target_link_libraries(my_target PUBLIC serial)

This PR also disable Catkin dependency by default, you can restore it by setting USE_CATKIN option to ON.

Also the option BUILD_SAMPLE allow you to build or not the sample (default is ON).

This is somewhat #133 is trying to do while keeping Catkin dependency as an option if needed.

[cz172638]

why not to squash all commit to one?

[cz172638]

why forcing static?
better would be to use -DBUILD_SHARED_LIBS=OFF (see https://cmake.org/cmake/help/v3.0/variable/BUILD_SHARED_LIBS.html)

[lukadt]

Can this pull request be fixed and merged? Having Catkin dependency as optional is a long time request

[traversaro]

Suggested change

	target_include_directories(${PROJECT_NAME} PUBLIC $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/include>)
	target_include_directories(${PROJECT_NAME} PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>)

The use of CMAKE_CURRENT_SOURCE_DIR is problematic when the project is used inside a bigger project via add_subdirectory , for example when using the FetchContent CMake module. Use of CMAKE_CURRENT_SOURCE_DIR should remove any ambiguity.