cmake_minimum_required(VERSION 3.28)

if(NOT SUBPROJECT)

    project(InstallScript)

    # Top-level exe; built by "all"
    file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/main.cpp "int main() {}")

    add_executable(test.exe ${CMAKE_CURRENT_BINARY_DIR}/main.cpp)
    target_link_libraries(test.exe PRIVATE testLib)

    set(SUBPROJECT ON)  # Just so we can reuse current file for add_subdirectory
    add_subdirectory(. testlib EXCLUDE_FROM_ALL)  # Note: EXCLUDE_FROM_ALL (only build lib if used)

else()

    add_custom_command(
        OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/TheScript.sh
        COMMAND /bin/sh -c "echo '#!/bin/sh' > ${CMAKE_CURRENT_BINARY_DIR}/TheScript.sh"
        VERBATIM)

    add_library(testLib ${CMAKE_CURRENT_BINARY_DIR}/../main.cpp  # Reuse from exe
        ${CMAKE_CURRENT_BINARY_DIR}/TheScript.sh  # Bind to force generation
    )

    install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/TheScript.sh
        DESTINATION /tmp)

endif()