Linker error with CXX_MODULES

Both libs are header only build as CXX_MODULES

bash-5.3$ dyld_info libboost_type_index.1.90.0.dylib
libboost_type_index.1.90.0.dylib [x86_64]:
    -platform:
        platform     minOS      sdk
           macOS     14.0      14.0   
    -segments:
        load-offset   segment section        sect-size  seg-size perm
        0x00000000    __TEXT                                 8KB r.x
        0x00001F10             __text               70
        0x00001F56             __stubs              12
        0x00001F62             __const              57
        0x00001F9C             __unwind_info        96
        0x00002000    __DATA_CONST                           4KB rw.
        0x00002000             __got                16
        0x00002010             __const              64
    -dependents:
        attributes     load path
                       /usr/local/opt/llvm/lib/c++/libc++abi.1.dylib
                       /usr/local/opt/llvm/lib/c++/libc++.1.dylib
                       /usr/lib/libSystem.B.dylib
bash-5.3$ dyld_info libboost_any.1.90.0.dylib
libboost_any.1.90.0.dylib [x86_64]:
    -platform:
        platform     minOS      sdk
           macOS     14.0      14.0   
    -segments:
        load-offset   segment section        sect-size  seg-size perm
        0x00000000    __TEXT                                 8KB r.x
        0x00001BD0             __text              768
        0x00001ED0             __stubs              12
        0x00001EDC             __cstring            61
        0x00001F19             __const             119
        0x00001F90             __unwind_info       112
        0x00002000    __DATA_CONST                           4KB rw.
        0x00002000             __got                24
        0x00002018             __const             192
    -dependents:
        attributes     load path
                       /usr/local/opt/llvm/lib/c++/libc++abi.1.dylib
                       /usr/local/opt/llvm/lib/c++/libc++.1.dylib
                       @rpath/libboost_type_index.1.90.0.dylib
                       /usr/lib/libSystem.B.dylib
bash-5.3$ dyld_info libboost_a.1.90.0.dylib
libboost_any.1.90.0.dylib     libboost_any.dylib            libboost_atomic.1.90.0.dylib  libboost_atomic.dylib         
bash-5.3$ dyld_info libboost_atomic.1.90.0.dylib
libboost_atomic.1.90.0.dylib [x86_64]:
    -platform:
        platform     minOS      sdk
           macOS     14.0      14.0   
    -segments:
        load-offset   segment section        sect-size  seg-size perm
        0x00000000    __TEXT                                12KB r.x
        0x00002010             __text             3370
        0x00002D3A             __stubs             126
        0x00002DB8             __gcc_except_tab    284
        0x00002ED4             __unwind_info       296
        0x00003000    __DATA_CONST                           4KB rw.
        0x00003000             __got               184
        0x00004000    __DATA                                36KB rw.
        0x00004000             __data            32776
        0x0000C008             __bss                 1
    -dependents:
        attributes     load path
                       /usr/local/opt/llvm/lib/c++/libc++abi.1.dylib
                       /usr/local/opt/llvm/lib/c++/libc++.1.dylib
                       /usr/lib/libSystem.B.dylib
bash-5.3$ 

see too Header-only libraries and C++20 modules

and type_index/modules/boost_type_index.cppm at develop · boostorg/type_index · GitHub