diff -ru xpdf-4.02.orig/CMakeLists.txt xpdf-4.02/CMakeLists.txt

--- xpdf-4.02.orig/CMakeLists.txt	2019-09-25 21:54:33.000000000 +0200

+++ xpdf-4.02/CMakeLists.txt	2020-07-03 18:16:19.639269162 +0200

@@ -28,10 +28,6 @@

   message(WARNING "Couldn't find libpng -- will not build pdftopng or pdftohtml.")

 endif ()

-if (NOT QT4_FOUND AND NOT Qt5Widgets_FOUND)

-  message(WARNING "Couldn't find Qt4 or Qt5 -- will not build xpdf.")

-endif ()

-

 if (NOT MULTITHREADED)

   message(WARNING "Multithreading is disabled -- will not build xpdf.")

 endif ()