With a recent change
g++ -DHAVE_CONFIG_H -I. -I.. -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/qt5/QtCore -I/usr/include/qt5 -I/usr/include/qt5/QtGui -I/usr/include/qt5/QtNetwork -I/usr/include/qt5/QtOpenGL -I/usr/include/qt5/QtWidgets -I/usr/include/qt5/QtPrintSupport -Ilibgui/graphics -I../libgui/graphics -Isrc -I../libgui/src -I../liboctave/array -Iliboctave/numeric -I../liboctave/numeric -Iliboctave/operators -I../liboctave/operators -I../liboctave/system -I../liboctave/util -Ilibinterp -I../libinterp -Ilibinterp/parse-tree -I../libinterp/parse-tree -Ilibinterp/corefcn -I../libinterp/corefcn -I../libinterp/octave-value -fPIC -pthread -fopenmp -Wall -W -Wshadow -Wold-style-cast -Wformat -Wpointer-arith -Wwrite-strings -Wcast-align -Wcast-qual -g -O2 -MT libgui/graphics/libgui_graphics_libgui_graphics_la-Figure.lo -MD -MP -MF libgui/graphics/.deps/libgui_graphics_libgui_graphics_la-Figure.Tpo -c ../libgui/graphics/Figure.cc -fPIC -DPIC -o libgui/graphics/.libs/libgui_graphics_libgui_graphics_la-Figure.o
../libgui/graphics/Figure.cc: In member function ‘void QtHandles::Figure::fileSaveFigure(bool)’:
../libgui/graphics/Figure.cc:882:79: error: expected ‘)’ before ‘;’ token
QFileDialog::DontUseNativeDialog);
See also e.g.: