RESOURCE
Specify resource files in a FRAMEWORK or BUNDLE.
Target marked with the FRAMEWORK or BUNDLE property generate framework or application bundle (both macOS and iOS is supported) or normal shared libraries on other platforms. This property may be set to a list of files to be placed in the corresponding directory (eg. Resources directory for macOS) inside the bundle. On non-Apple platforms these files may be installed using the RESOURCE option to the install(TARGETS) command.
Following example of Application Bundle:
add_executable(ExecutableTarget
  addDemo.c
  resourcefile.txt
  appresourcedir/appres.txt)
target_link_libraries(ExecutableTarget heymath mul)
set(RESOURCE_FILES
  resourcefile.txt
  appresourcedir/appres.txt)
set_target_properties(ExecutableTarget PROPERTIES
  MACOSX_BUNDLE TRUE
  MACOSX_FRAMEWORK_IDENTIFIER org.cmake.ExecutableTarget
  RESOURCE "${RESOURCE_FILES}")
 will produce flat structure for iOS systems:
ExecutableTarget.app appres.txt ExecutableTarget Info.plist resourcefile.txt
For macOS systems it will produce following directory structure:
ExecutableTarget.app/
  Contents
    Info.plist
    MacOS
      ExecutableTarget
    Resources
      appres.txt
      resourcefile.txt
 For Linux, such CMake script produce following files:
ExecutableTarget Resources appres.txt resourcefile.txt
    © 2000–2020 Kitware, Inc. and Contributors
Licensed under the BSD 3-clause License.
    https://cmake.org/cmake/help/v3.15/prop_tgt/RESOURCE.html