If it is not problematic, please retain support for Qt4

[barracuda156]

Not sure whether it is a burden or not, but if possible, it will be nice to keep Qt4 support.

P. S. Opening an issue due to this:

-- Using Qt4 and libpoppler-qt4
CMake Warning at cmake/external_libraries.cmake:105 (message):
  Qt4 support is deprecated and will be removed in the next version.  Please
  build dspdfviewer using Qt5.  If that does not work correctly on your
  platform, please file a bug!

[Rondom]

Out of interest: What exactly is your use case for QT4 in 2024?

[barracuda156]

Out of interest: What exactly is your use case for QT4 in 2024?

Qt5+ is broken on older macOS (and all powerpc and i386), and perspectives of fixing it are unclear at the moment. Upstream made considerable efforts to have it broken. Fixing will be a huge work, likely requiring rewriting the codebase to use X11 instead of a broken Cocoa (since Carbon support was removed, and restoring it is non-trivial if possible at all).