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 ()