CMakeLists.txt

add_library(hello SHARED src/hello.cc)
target_include_directories(
  hello PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
               $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
install(TARGETS hello LIBRARY DESTINATION _csrc)

add_library(complexf SHARED src/complexf.cc)
target_include_directories(
  complexf PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
                  $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
target_link_libraries(complexf PRIVATE hello)
install(TARGETS complexf LIBRARY DESTINATION _csrc)
set_target_properties(complexf PROPERTIES INSTALL_RPATH "$ORIGIN")

# install(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/include/" DESTINATION
# ${CMAKE_INSTALL_INCLUDEDIR}) set(HELLO_CMAKE_PACKAGE_INSTALL_SUBDIR
# "share/hello/cmake")

# install( EXPORT helloTargets NAMESPACE hello:: DESTINATION
# ${HELLO_CMAKE_PACKAGE_INSTALL_SUBDIR})