[Issue 19553] runnable/cpp_stdlib.d fails on NixOS

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19553

--- Comment #3 from Thomas Mader <thomas.mader at gmail.com> ---
The problem is that NixOS is using some flags for hardening on gcc.
The problematic flag is '-O2' which is used in conjunction with
'-D_FORTIFY_SOURCE=2'.
If this is used when compiling extra-files/cpp_stdlib.cpp or
extra-files/cppb.cpp a lot of symbols are missing in the resulting object file.

The question now is if it is possible somehow to make sure that no hidden flags
are passed to those tests so that such problems can not occur.

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