Why does align_image_stack need wxwidgets?

wxWidgets is framework for applications, not only for GUI.
Some applications in the Hugin bundle require wxWidgets. There are some application (e.g. align_image_stack), which don't require wxWidgets. Building without wxWidgets would require some changes to the build system and then some core applications of Hugin could not build anymore.
Beside this there is also a flatpak of Hugin available on Flathub.

OK. the "flatpak of Hugin available on Flathub" won't help me, but I could copy relevant information out of the Flatpak manifest for Hugin. Do you know where I might find this?

Could you please clarify your explanation?

"some application (e.g. align_image_stack), which don't require wxWidgets."
     This means to me that I CAN build align-image-stack without wxwidgets.

"Building without wxWidgets would require some changes to the build system"
     This means to me that I CANNOT build align-image-stack without wxwidgets.

"Building without wxWidgets would require some changes to the build system and then some core applications of Hugin could not build anymore."
     This means to me that I CAN build align-image-stack without wxwidgets, but CANNOT build Hugin without wxwidgets.

This suggests that wxwidgets is required by align-image-stack:

> Building module align_image_stack in /home/chris/.flatpak-builder/build/align_image_stack-1
> -- The C compiler identification is GNU 10.2.0
> -- The CXX compiler identification is GNU 10.2.0
> -- Detecting C compiler ABI info
> -- Detecting C compiler ABI info - done
> -- Check for working C compiler: /usr/bin/cc - skipped
> -- Detecting C compile features
> -- Detecting C compile features - done
> -- Detecting CXX compiler ABI info
> -- Detecting CXX compiler ABI info - done
> -- Check for working CXX compiler: /usr/bin/c++ - skipped
> -- Detecting CXX compile features
> -- Detecting CXX compile features - done
> -- Current HG revision is 5abfb4de7961
> -- Assuming this is a tarball (release) build for 2018.0.0
> -- Looking for log1p
> -- Looking for log1p - found
> CMake Error at /usr/share/cmake-3.19/Modules/FindPackageHandleStandardArgs.cmake:218 (message):
> Could NOT find wxWidgets (missing: wxWidgets_LIBRARIES
> wxWidgets_INCLUDE_DIRS)
> Call Stack (most recent call first):
> /usr/share/cmake-3.19/Modules/FindPackageHandleStandardArgs.cmake:577 (_FPHSA_FAILURE_MESSAGE)
> /usr/share/cmake-3.19/Modules/FindwxWidgets.cmake:1016 (find_package_handle_standard_args)
> CMakeLists.txt:166 (FIND_PACKAGE)
> -- Configuring incomplete, errors occurred!

This question was expired because it remained in the 'Open' state without activity for the last 15 days.