SOURCES = main.cpp #! [0] CONFIG += opengl #! [0] #! [1] opengl { TARGET = application-gl } else { #! [1] #! [2] TARGET = application #! [2] #! [3] } #! [3] #! [4] CONFIG(opengl) { message(Building with OpenGL support.) } else { #! [4] #! [5] message(OpenGL support is not available.) } #! [5]