src/rp2_common/pico_clib_interface/CMakeLists.txt

if (NOT TARGET pico_clib_interface)
    pico_add_library(pico_clib_interface)

    # ---- newlib ----
    pico_add_library(pico_newlib_interface)

    target_sources(pico_newlib_interface INTERFACE
            ${CMAKE_CURRENT_LIST_DIR}/newlib_interface.c
    )

    # ---- picolibc ----

    pico_add_library(pico_picolibc_interface)

    target_sources(pico_picolibc_interface INTERFACE
            ${CMAKE_CURRENT_LIST_DIR}/picolibc_interface.c
    )

    # replacing the functions is fine it seems
    #target_compile_definitions(pico_picolibc_interface INTERFACE
    #            PICO_STDIO_SHORT_CIRCUIT_CLIB_FUNCS=0
    #)

    #  ---- llvm_libc ----
    pico_add_library(pico_llvm_libc_interface)

    target_sources(pico_llvm_libc_interface INTERFACE
            ${CMAKE_CURRENT_LIST_DIR}/llvm_libc_interface.c
    )

    target_include_directories(pico_llvm_libc_interface SYSTEM INTERFACE
            ${CMAKE_CURRENT_LIST_DIR}/include/llvm_libc
    )
    target_link_libraries(pico_llvm_libc_interface INTERFACE pico_atomic)
    pico_mirrored_target_link_libraries(pico_llvm_libc_interface INTERFACE pico_stdio)

    if (NOT PICO_CLIB)
        set(PICO_CLIB newlib)
    endif()

    target_link_libraries(pico_clib_interface INTERFACE pico_${PICO_CLIB}_interface)
endif()