optional_depends OPENGL                              \
                 "--with-opengl"                     \
                 "--without-opengl"                  \
                 "Use OpenGL for smoother scaling?"  &&
optional_depends libpng                              \
                 "--with-newblend"                   \
                 "--without-newblend"                \
                 "New colour blender?"               &&
optional_depends nasm                                \
                 "--with-assembler"                  \
                 "--without-assembler"               \
                 "Use assembler cores?"              &&
depends  X11-LIBS "--with-x"                         &&
depends  zlib "--with-zlib"
