CMakeLists.txt

pybind11_add_module(pyFooBar MODULE pyFooBar.cpp)
# note: macOS is APPLE and also UNIX !
if(APPLE)
  set_target_properties(pyFooBar PROPERTIES
    SUFFIX ".so"
    INSTALL_RPATH "@loader_path;@loader_path/../../${PYTHON_PROJECT}/.libs"
    )
  set_property(TARGET pyFooBar APPEND PROPERTY
    LINK_FLAGS "-flat_namespace -undefined suppress"
    )
elseif(UNIX)
  set_target_properties(pyFooBar PROPERTIES
    INSTALL_RPATH "$ORIGIN:$ORIGIN/../../${PYTHON_PROJECT}/.libs"
    )
endif()
target_link_libraries(pyFooBar PRIVATE ${PROJECT_NAMESPACE}::FooBar)
add_library(${PROJECT_NAMESPACE}::pyFooBar ALIAS pyFooBar)

#set_property(SOURCE foobar.i PROPERTY CPLUSPLUS ON)
#set_property(SOURCE foobar.i PROPERTY SWIG_MODULE_NAME pyFooBar)
#swig_add_library(pyFooBar
#  TYPE SHARED
#  LANGUAGE python
#  OUTPUT_DIR ${CMAKE_BINARY_DIR}/python/${PYTHON_PROJECT}/foobar
#  SOURCES foobar.i)
#add_library(${PROJECT_NAMESPACE}::pyFooBar ALIAS pyFooBar)
#
#target_include_directories(pyFooBar
#  PRIVATE
#  ../include
#  ${Python3_INCLUDE_DIRS}
#  )
#set_property(TARGET pyFooBar PROPERTY SWIG_USE_TARGET_INCLUDE_DIRECTORIES ON)
#
## note: macOS is APPLE and also UNIX !
#if(APPLE)
#  set_target_properties(pyFooBar PROPERTIES
#    SUFFIX ".so"
#    INSTALL_RPATH "@loader_path;@loader_path/../../${PYTHON_PROJECT}/.libs"
#    )
#  set_property(TARGET pyFooBar APPEND PROPERTY
#    LINK_FLAGS "-flat_namespace -undefined suppress"
#    )
#elseif(UNIX)
#  set_target_properties(pyFooBar PROPERTIES
#    INSTALL_RPATH "$ORIGIN:$ORIGIN/../../${PYTHON_PROJECT}/.libs"
#    )
#endif()
#target_link_libraries(pyFooBar PRIVATE ${PROJECT_NAMESPACE}::FooBar)
#
## Variable PYTHON_LIBRARIES can contains keyword `optimized`
## which won't be interpreted inside a generator expression.
## i.e. we can't use: $<$<PLATFORM_ID:Windows>:${PYTHON_LIBRARIES}>
## see: https://cmake.org/cmake/help/git-stage/command/target_link_libraries.html#command:target_link_libraries
#if(MSVC)
#  target_link_libraries(pyFooBar PRIVATE ${Python3_LIBRARIES})
#endif()