How to cross-compile libgphoto2 (to aarch64 on Ubuntu/Debian)?

[axxel]

I'm trying to cross-compile to aarch64. I installed crossbuild-essential-arm64 and now have a working compiler and toolchain, meaning I can compile a hello-world program and run it happily.

Next step was

configure --build x86_64-pc-linux-gnu --host aarch64-linux-gnu --enable-mpers=check
    --disable-nls --without-jpeg --with-libxml-2.0=no --with-libexif=no --with-libcurl=no --with-gdlib=no
    --disable-serial --with-camlibs=ptp2
    --disable-shared --enable-static  CFLAGS="-g"

trying to make it as easy as possible by removing all unnecessary dependencies. configure fails with the following error:

configure: error: 
libgphoto2 requires libltdl (a part of libtool)

Why is libltdl still required if I --disable-shared?

I'd appreciate any hints towards either:

• get configure find the missing libltdl
• compile libgphoto2/libgphoto_port with statically linked ptp2 camlib and libusb driver, to remove the libltdl dependency

Maybe @ndim or @hfiguiere have some relevant insights?

[ndim]

Whether you build libgphoto2 and libgphoto2_port as a static or as a dynamic library makes no difference here. They both unconditionally use libltdl to dynamically load camlibs (camera drivers) or iolibs (port drivers), respectively.

[axxel]

Thanks for the clarification. Maybe the real question is: why? What is the use case for having a static build that still loads dlls at runtime?

Is there maybe some "hack" that could be applied to the build system to link those symbols statically into the library?

[ndim]

The variables to set for building with your custom libltdl:

$ ./configure --help | grep -i ltdl
  LTDLINCL    CFLAGS for compiling with libltdl
  LIBLTDL     LIBS to add for linking against libltdl
$ _