else
PKG_CHECK_MODULES([SDL_image], [SDL_image], [], [with_demo_app=no; AC_MSG_WARN([SDL_image not found, demo program will not be built])])
fi
-PKG_CHECK_MODULES([libpng], [libpng12], [], [with_demo_app=no; AC_MSG_WARN([libpng12 not found, demo program will not be built])])
+PKG_CHECK_MODULES([libpng], [libpng], [], [with_demo_app=no; AC_MSG_WARN([libpng not found, demo program will not be built])])
AC_SUBST([with_demo_app])
AC_SUBST([with_SDL2])