-@code{ada}, @code{c}, @code{c++}, @code{f77}, @code{f95}, @code{java},
-@code{objc}, @code{obj-c++}.
-Building the Ada compiler has special requirements, see below.@*
-If you do not pass this flag, all languages available in the @file{gcc}
-sub-tree will be configured. Re-defining @code{LANGUAGES} when calling
-@samp{make bootstrap} @strong{does not} work anymore, as those
-language sub-directories might not have been configured!
+@code{all}, @code{ada}, @code{c}, @code{c++}, @code{f95}, @code{java},
+@code{objc}, @code{obj-c++}, @code{treelang}.
+Building the Ada compiler has special requirements, see below.
+If you do not pass this flag, or specify the option @code{all}, then all
+default languages available in the @file{gcc} sub-tree will be configured.
+Ada, Objective-C++, and treelang are not default languages; the rest are.
+Re-defining @code{LANGUAGES} when calling @samp{make bootstrap}
+@strong{does not} work anymore, as those language sub-directories might
+not have been configured!