qfloat16_f16c warning/error with clang 5.0.0

❯ ../src/configure -developer-build -commercial -confirm-license -debug -platform linux-clang
[...]
❯ make
[...]
clang++ -c -pipe -g -Og -std=c++1z -fvisibility=hidden -fvisibility-inlines-hidden -Wall -W -Wdate-time -Werror -Wno-error=#warnings -Wno-error=deprecated-declarations -D_REENTRANT -fPIC -DQT_NO_USING_NAMESPACE -DQT_NO_FOREACH -DELF_INTERPRETER=\"/lib64/ld-linux-x86-64.so.2\" -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_CORE_LIB -DQT_BUILDING_QT -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x050000 -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -mf16c -I/home/juri/p/qt/qt5-dev/src/qtbase/src/corelib -I. -Iglobal -I/home/juri/p/qt/qt5-dev/src/qtbase/src/3rdparty/harfbuzz/src -I/home/juri/p/qt/qt5-dev/src/qtbase/src/3rdparty/md5 -I/home/juri/p/qt/qt5-dev/src/qtbase/src/3rdparty/md4 -I/home/juri/p/qt/qt5-dev/src/qtbase/src/3rdparty/sha3 -I/home/juri/p/qt/qt5-dev/src/qtbase/src/3rdparty/forkfd -I../../include -I../../include/QtCore -I../../include/QtCore/5.11.0 -I../../include/QtCore/5.11.0/QtCore -I.moc -isystem /usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/home/juri/p/qt/qt5-dev/src/qtbase/mkspecs/linux-clang /home/juri/p/qt/qt5-dev/src/qtbase/src/corelib/global/qfloat16_f16c.c -o .obj/qfloat16_f16c.o
clang-5.0: error: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Werror,-Wdeprecated]
make[3]: *** [Makefile:16885: .obj/qfloat16_f16c.o] Error 1
make[3]: Leaving directory '/home/juri/p/qt/qt5-dev/out/qtbase/src/corelib'
make[2]: *** [Makefile:171: sub-corelib-make_first] Error 2
make[2]: Leaving directory '/home/juri/p/qt/qt5-dev/out/qtbase/src'
make[1]: *** [Makefile:49: sub-src-make_first] Error 2
make[1]: Leaving directory '/home/juri/p/qt/qt5-dev/out/qtbase'
make: *** [Makefile:60: module-qtbase-make_first] Error 2
make  249,36s user 9,69s system 97% cpu 4:24,88 total