Bump min CMake/Qt/KF deps to 3.16/5.15/5.85

CMakeLists.txt

-cmake_minimum_required (VERSION 3.5 FATAL_ERROR)
+cmake_minimum_required (VERSION 3.16 FATAL_ERROR)
 
 set(KDEGAMES_VERSION 7.3.0)
 set(KDEGAMES_SOVERSION 7)
 
 project(libkdegames)
 
-set (QT_MIN_VERSION "5.12.0")
-set (KF_MIN_VERSION "5.68.0")
+set (QT_MIN_VERSION "5.15.0")
+set (KF_MIN_VERSION "5.85.0")
 
 find_package(ECM ${KF_MIN_VERSION} REQUIRED NO_MODULE)
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules ${ECM_MODULE_PATH})
@@ -81,19 +81,11 @@ set(KGAUDIO_BACKEND_OPENAL TRUE) # for configure_file() below
 add_definitions(-DTRANSLATION_DOMAIN="libkdegames5")
 
 add_definitions(
-    -DQT_DEPRECATED_WARNINGS
     -DQT_DISABLE_DEPRECATED_BEFORE=0x050900
     -DQT_DEPRECATED_WARNINGS_SINCE=0x060000
-    -DQT_NO_FOREACH
-    -DQT_NO_KEYWORDS
-    -DQT_NO_URL_CAST_FROM_STRING
-    -DQT_NO_CAST_FROM_ASCII
-    -DQT_NO_CAST_TO_ASCII
-    -DQT_NO_CAST_FROM_BYTEARRAY
-    -DQT_STRICT_ITERATORS
-    -DQT_USE_QSTRINGBUILDER
-    -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT
-    -DKF_DISABLE_DEPRECATED_BEFORE_AND_AT=0x052e00
+    -DKF_DISABLE_DEPRECATED_BEFORE_AND_AT=0x055400
+    -DKCOREADDONS_DISABLE_DEPRECATED_BEFORE_AND_AT=0x054900 # KRandomSequence, cannot be removed
+    -DKNEWSTUFF_DISABLE_DEPRECATED_BEFORE_AND_AT=0x054F00 # KNS3::DownloadDialog -> needs porting
     -DKF_DEPRECATED_WARNINGS_SINCE=0x060000
 )