> We have, per 'gcc/doc/install.texi':
>
> @item --enable-languages=@var{lang1},@var{lang2},@dots{}
> [...]
> Currently, you can use any of the following:
> @code{all}, @code{default}, @code{ada}, @code{c}, @code{c++},
> @code{cobol}, @code{d}, @code{fortran}, @code{go}, @code{jit},
> @code{lto}, @code{m2}, @code{objc}, @code{obj-c++}.
> [...]
> If you do not pass this flag, or specify the option @code{default}, then
> the default languages available in the @file{gcc} sub-tree will be
> configured. Ada, COBOL, D, Go, Jit, Objective-C++ and Modula-2 are not
> default languages. LTO is not a
> default language, but is built by default because @option{--enable-lto}
> is enabled by default. The other languages are default languages.
FWIW Rust is not built by default either:
eric@fomalhaut:~/cvs/gcc/gcc> grep build_by_default */config-lang.in */*/
config-lang.in
cobol/config-lang.in:build_by_default="no"
d/config-lang.in:build_by_default="no"
go/config-lang.in:build_by_default="no"
jit/config-lang.in:build_by_default="no"
lto/config-lang.in:build_by_default=no
m2/config-lang.in:build_by_default="no"
objcp/config-lang.in:build_by_default="no"
rust/config-lang.in:build_by_default="no"
ada/gcc-interface/config-lang.in:build_by_default=no
--
Eric Botcazou
