After removing kdelibs4support, these flags are enabled:
-DQT_USE_FAST_OPERATOR_PLUS -DQT_NO_CAST_TO_ASCII
-DQT_NO_CAST_FROM_ASCII -DQT_NO_URL_CAST_FROM_STRING
-DQT_NO_CAST_FROM_BYTEARRAY
So wrap naked string and character literals in QStringLiteral,
QLatin1Char and QLatin1String as appropriate.
To more easily see the changes, use «git show --color-words».
Thank $DEITY for vim macros.