the appindicator patch to g-s-d breaks compilation for appindicator-less case

Binary package hint: gnome-settings-daemon

As of 2.32.0-0ubuntu3, the automake-fu, as listed on https://wiki.ubuntu.com/DesktopExperienceTeam/ApplicationIndicators#Automake%20fu, has been applied wrongly, for no visible reason. Namely, the original bit:

AC_ARG_ENABLE(appindicator,
                        AS_HELP_STRING([--enable-appindicator[=@<:@no/auto/yes@:>@]],[Build support for application indicators ]),
                        [enable_appindicator=$enableval],
                        [enable_appindicator="auto"])

has been instead changed to:

AC_ARG_ENABLE([appindicator],
 AS_HELP_STRING([--enable-appindicator[=@<:@no/auto/yes@:>@]],[Build support for application indicators]),
 [enable_appindicator="yes"],
 [enable_appindicator="auto"])

Due to the way automake snippets are expanded and organised, this has the effect of ignoring the actual value supplied to --enable-appindicator and always substituting "yes" instead. The original form of '[enable_appindicator=$enableval]' should be restored to fix it.