--- "Qt5LinguistToolsMacros - Copy.cmake"	2020-03-27 20:21:55.000000000 +0000
+++ Qt5LinguistToolsMacros.cmake	2020-08-21 18:01:36.519699900 +0100
@@ -41,6 +41,17 @@
     set(_lupdate_files ${_LUPDATE_UNPARSED_ARGUMENTS})
     set(_lupdate_options ${_LUPDATE_OPTIONS})
 
+    if("-extensions" IN_LIST _lupdate_options)
+        list(FIND ${_lupdate_options} "-extensions" _extensions_index)
+        math(EXPR _extensions_index "${_extensions_index} + 1")
+        list(GET ${_lupdate_options} ${_extensions_index} _extensions_list)
+        string(REPLACE "," ";" _extensions_list "${_extensions_list}")
+        list(TRANSFORM _extensions_list STRIP)
+        list(TRANSFORM _extensions_list REPLACE "^\." "")
+        list(TRANSFORM _extensions_list PREPEND "*.")
+    else()
+        set(_extensions_list "*.java;*.jui;*.ui;*.c;*.c++;*.cc;*.cpp;*.cxx;*.ch;*.h;*.h++;*.hh;*.hpp;*.hxx;*.js;*.qs;*.qml;*.qrc")
+    endif()
     set(_my_sources)
     set(_my_tsfiles)
     foreach(_file ${_lupdate_files})
@@ -59,8 +70,16 @@
           get_filename_component(_ts_name ${_ts_file} NAME)
           set(_ts_lst_file "${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/${_ts_name}_lst_file")
           set(_lst_file_srcs)
+          set(_dependencies)
           foreach(_lst_file_src ${_my_sources})
               set(_lst_file_srcs "${_lst_file_src}\n${_lst_file_srcs}")
+              if(IS_DIRECTORY ${_lst_file_src})
+                  list(TRANSFORM _extensions_list PREPEND "${_lst_file_src}/" OUTPUT_VARIABLE _directory_glob)
+                  file(GLOB_RECURSE _directory_contents CONFIGURE_DEPENDS ${_directory_glob})
+                  list(APPEND _dependencies ${_directory_contents})
+              else()
+                  list(APPEND _dependencies "${_lst_file_src}")
+              endif()
           endforeach()
 
           get_directory_property(_inc_DIRS INCLUDE_DIRECTORIES)
@@ -74,7 +93,7 @@
         add_custom_command(OUTPUT ${_ts_file}
             COMMAND ${Qt5_LUPDATE_EXECUTABLE}
             ARGS ${_lupdate_options} "@${_ts_lst_file}" -ts ${_ts_file}
-            DEPENDS ${_my_sources}
+            DEPENDS ${_dependencies}
             BYPRODUCTS ${_ts_lst_file} VERBATIM)
     endforeach()
     qt5_add_translation(${_qm_files} ${_my_tsfiles})