I suppose I should be more explicit:
strace -e file -f -o strace.log /home/sigis/.local/bin/zig-c++ -target x86_64-macos-none -DQT_CORE_LIB -DQT_GUI_LIB -DQT_NO_DEBUG -DQT_WIDGETS_LIB -I/home/sigis/prg/qt/qt-example/build/mac-qt-zig/src/qtdemo -I/home/sigis/prg/qt/qt-example/src/qtdemo -I/home/sigis/prg/qt/qt-example/build/mac-qt-zig/src/qtdemo/qtdemo_autogen/include -I/opt/qt/5.15.2/clang_64/lib -isystem /opt/qt/5.15.2/clang_64/lib/QtWidgets.framework -isystem /opt/qt/5.15.2/clang_64/lib/QtWidgets.framework/Headers -isystem /opt/qt/5.15.2/clang_64/lib/QtGui.framework -isystem /opt/qt/5.15.2/clang_64/lib/QtGui.framework/Headers -isystem /System/Library/Frameworks/OpenGL.framework/Headers -isystem /opt/qt/5.15.2/clang_64/lib/QtCore.framework -isystem /opt/qt/5.15.2/clang_64/lib/QtCore.framework/Headers -isystem /opt/qt/5.15.2/clang_64/./mkspecs/macx-clang -Wall -O3 -DNDEBUG -fPIC -MD -MT src/qtdemo/CMakeFiles/qtdemo.dir/main.cpp.o -MF src/qtdemo/CMakeFiles/qtdemo.dir/main.cpp.o.d -o src/qtdemo/CMakeFiles/qtdemo.dir/main.cpp.o -c /home/sigis/prg/qt/qt-example/src/qtdemo/main.cpp