headersclean fails on QNX 7

qcc -Vgcc_ntoarmv7le -c -mfpu=neon -Wno-psabi -lang-c++ -O3 -Wc,-std=gnu++1z -fvisibility=hidden -fvisibility-inlines-hidden -Wall -W -Wvla -Wdate-time -Werror -Wno-error=cpp -Wno-error=deprecated-declarations -Wno-error=strict-overflow -D_REENTRANT -fPIC -shared -DQT_NO_USING_NAMESPACE -DQT_NO_FOREACH -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 -DQT_NO_DEBUG -DPCRE2_CODE_UNIT_WIDTH=16 -Wall -Wextra -Werror -Woverloaded-virtual -Wshadow -Wundef -Wfloat-equal -Wnon-virtual-dtor -Wpointer-arith -Wformat-security -Wno-long-long -Wno-variadic-macros -pedantic-errors -Wchar-subscripts -Wold-style-cast -Wdouble-promotion -Wzero-as-null-pointer-constant -I. -Iglobal -I../3rdparty/harfbuzz/src -I../3rdparty/md5 -I../3rdparty/md4 -I../3rdparty/sha3 -I../3rdparty/double-conversion/include -I../3rdparty/double-conversion/include/double-conversion -I../3rdparty/forkfd -I../../include -I../../include/QtCore -I../../include/QtCore/5.9.0 -I../../include/QtCore/5.9.0/QtCore -I.moc -I../3rdparty/pcre2/src -I/opt/qnx700/target/qnx7/usr/include -I/opt/qnx700/target/qnx7/usr/include/freetype2 -I../../mkspecs/qnx-armle-v7-qcc -DQT_NO_CAST_TO_ASCII=1 -DQT_NO_CAST_FROM_ASCII=1 -DQT_STRICT_ITERATORS -DQT_NO_URL_CAST_FROM_STRING=1 -DQT_NO_CAST_FROM_BYTEARRAY=1 -DQT_NO_KEYWORDS=1 -DQT_USE_QSTRINGBUILDER -DQT_USE_FAST_OPERATOR_PLUS -Dsignals=int -Dslots=int -Demit=public: -Dforeach=public: -Dforever=public: -xc++ kernel/qsocketnotifier.h -o .obj/header_qsocketnotifier.o
kernel/qdeadlinetimer.h: In constructor 'constexpr std::__1::chrono::duration<_Rep, _Period>::duration(const _Rep2&, typename std::__1::enable_if<(std::__1::is_convertible<_U1, _T1>::value && (std::__1::chrono::treat_as_floating_point<_Rep>::value || (! std::__1::chrono::treat_as_floating_point<_Rep2>::value)))>::type*) [with _Rep2 = long long int; _Rep = long long int; _Period = std::__1::ratio<1ll, 1000000000ll>; typename std::__1::enable_if<(std::__1::is_convertible<_U1, _T1>::value && (std::__1::chrono::treat_as_floating_point<_Rep>::value || (! std::__1::chrono::treat_as_floating_point<_Rep2>::value)))>::type = void]':
kernel/qdeadlinetimer.h:163:46: error: zero as null pointer constant [-Werror=zero-as-null-pointer-constant]
         return std::chrono::nanoseconds(nsecs);
                                              ^
cc1plus: all warnings being treated as errors