[Issue 18120] Allow DRT options to be set via the environment

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18120

Rainer Schuetze <r.sagitario at gmx.de> changed:

           What    |Removed                     |Added
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                 CC|                            |r.sagitario at gmx.de

--- Comment #1 from Rainer Schuetze <r.sagitario at gmx.de> ---
If grabbed via rt_configOption, the DRT options are read from the environment
variable "DRT_<OPT>" if rt_envvars_enabled is set in the binary. See
https://dlang.org/spec/garbage.html#gc_config for an example.

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