Want to write ldc2.conf

[NonNull]

On Saturday, 3 August 2019 at 20:22:52 UTC, NonNull wrote:
> Where can I find how to add -Imydir and -Lmylib.lib to 
> ldc2.conf to add to the existing configuration of ldc2?

I looked here:

https://github.com/ldc-developers/ldc/blob/master/driver/config.d

because the comment in etc/ldc2.conf in the binary distribution 
of ldc2 I am using said to do that in a comment.

But this just gives me a grammar without any semantics.

I looked here:
https://wiki.dlang.org/Using_LDC
and it tells you where to put lcd2.conf if you write your own.

This seems to suggest that only one such file will be read, the 
first found in the search order. But it doesn't tell you how to 
write such a file.

I can edit a copy of the existing file and put it earlier in the 
search order. But that doesn't tell me what all the possibilities 
are.

Where is the documentation?