[Development] CI failing due to ASan tst_selftest

[Ulf Hermann]

>     ==19383==ERROR: LeakSanitizer: detected memory leaks
>   Direct leak of 48 byte(s) in 2 object(s) allocated from:
>         #0 0x7f26aec7ae48 in __interceptor_malloc (/usr/lib64/libasan.so.
> 5+0x109e48)
>         #1 0x7f26a8bcbc50  (/usr/lib64/libfontconfig.so.1+0xbc50)
>         #2 0x3d4c4c415f434bff  (<unknown module>)

I've seen this one before. I suspect certain versions of fontconfig have 
an internal memory leak. For me, it fixed itself after an upgrade of 
some packages. Can we install debug symbols for fontconfig on the 
respective platforms? Then we could see a proper stack trace.

best regards,
Ulf