`toolchain` variable

[toots]

It would be nice to provide a toolchain constant, whose value can be passed in: ocamlfind -toolchain %{toolchain} ...

[rgrinberg]

Feature granted.

[dboris]

Is this variable supposed to work in a dune file, eg (library (enabled_if (= %{toolchain} ios)) ...)? It doesn't seem to be supported. It would be nice if it was.

[rgrinberg]

Could you post the full library stanza?

[dboris]

Here's an example. If I try (enabled_if (= %{toolchain} ios)) in place of the (or (= %{context_name} default.ios) ...), I get an error:

4 |  (enabled_if (= %{toolchain} ios))
                    ^^^^^^^^^^^^
Error: Unknown variable %{toolchain}