configure adds -DBUILD_*=ON entries to config.opt

I ran

~/work/Qt-dev/configure -developer-build -no-optimize-debug \
    -submodules qtbase,qtdeclarative \
    -- -DQT_BUILD_TESTS_BY_DEFAULT=OFF -Wno-dev --log-level=NOTICE

(well, actually, without the backslash-linebreaks, added here to save a scroll-bar).
What landed in config.opt, however, was

-developer-build
-no-optimize-debug
-submodules
qtbase,qtdeclarative
--
-DBUILD_qtbase=ON
-DBUILD_qtdeclarative=ON
-DQT_BUILD_TESTS_BY_DEFAULT=OFF
-Wno-dev
--log-level=NOTICE

The two -DBUILD_*=ON lines were not present in the command-line I ran; they are presumably artefacts of the implementation of -submodules, but this file should surely contain a faithful record if what was actually on the command-line.