none of those is needed in fact. We use cmake-config files.

cmake/FindCORSIKA.cmake

-
-add_library(CORSIKA INTERFACE)
-
-target_compile_coptions(CORSIKA
-  INTERFACE
-  ${CMAKE_CURRENT_SOURCE_DIR})

cmake/FindCORSIKA8.cmake

-add_library (CORSIKA8 INTERFACE)
-
-target_include_directories (CORSIKA8
-  INTERFACE
-  ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})
-
-target_link_libraries (CORSIKA8 INTERFACE PhysUnits)
-
-set (CORSIKA8_FOUND TRUE)

cmake/FindCorsika8.cmake

-#
-# FindCorsika8
-#
-# This module tries to find the Corsika8 header files and extrats their version.  It
-# sets the following variables.
-#
-# CORSIKA8_FOUND       -  Set ON if Corsika8 headers are found, otherwise OFF.
-#
-# CORSIKA8_INCLUDE_DIR -  Include directory for hydra header files.  (All header
-#                       files will actually be in the Corsika8 subdirectory.)
-# CORSIKA8_VERSION     -  Version of hydra in the form "major.minor.patch".
-#
-
-find_path( CORSIKA8_INCLUDE_DIR
-  PATHS
-    ${CMAKE_SOURCE_DIR}
-    /usr/include
-    /usr/local/include
-    ${CORSIKA8_DIR}
-  NAMES corsika/corsika.h
-  DOC "Corsika8 headers"
-  )
-
-
-if( CORSIKA8_INCLUDE_DIR )
-  list( REMOVE_DUPLICATES CORSIKA8_INCLUDE_DIR )
-endif( CORSIKA8_INCLUDE_DIR )
-
-# Find hydra version
-if (CORSIKA8_INCLUDE_DIR)
-  file( STRINGS ${CORSIKA_INCLUDE_DIR}/corsika/corsika.h
-    version
-    REGEX "#define CORSIKA_VERSION[ \t]+([0-9x]+)"
-    )
-  string( REGEX REPLACE
-    "#define CORSIKA_VERSION[ \t]+"
-    ""
-    version
-    "${version}"
-    )
-
-  string( REGEX MATCH "^[0-9]" major ${version} )
-  string( REGEX REPLACE "^${major}00" "" version "${version}" )
-  string( REGEX MATCH "^[0-9]" minor ${version} )
-  string( REGEX REPLACE "^${minor}0" "" version "${version}" )
-  set( CORSIKA_VERSION "${major}.${minor}.${version}")
-  set( CORSIKA_MAJOR_VERSION "${major}")
-  set( CORSIKA_MINOR_VERSION "${minor}")
-endif()
-
-# Check for required components
-include( FindPackageHandleStandardArgs )
-find_package_handle_standard_args( Corsika8
-  FOUND_VAR CORSIKA8_FOUND
-  REQUIRED_VARS CORSIKA8_INCLUDE_DIR
-  VERSION_VAR CORSIKA8_VERSION
-  )
-
-if(CORSIKA8_FOUND)
-  set(CORSIKA8_INCLUDE_DIRS ${CORSIKA8_INCLUDE_DIR})
-endif()
-
-mark_as_advanced(CORSIKA8_INCLUDE_DIR)