Instruct gdc to look for standard library in another directory

[Johann]

On Saturday, 1 July 2023 at 15:36:55 UTC, Johann wrote:
> On Saturday, 1 July 2023 at 10:18:43 UTC, Iain Buclaw wrote:
>> Is it too much to ask downstream package maintainers to 
>> politely use `/usr/share/dlang/{ldc,dmd}` ? :-)
>
> Thanks for your help, Iain. I am going to report a bug to the 
> distro maintainers then.

Meanwhile, I found out the problem can be worked around by using 
`-nostdinc` option.


```
-nostdinc
     Do not search the standard system directories for D source 
and interface files.  Only the directories that have been 
specified with -I options (and the directory of the current file, 
if appropriate) are searched.
```