Please add -D_GLIBCXX_ASSERTIONS to default build flags

[Mark Esler]

> The _GLIBCXX_ASSERTIONS macro defines a subset of the _GLIBCXX_DEBUG
> checks, with no impact on class layout and minimal impact on runtime
> (and no changes in algorithmic complexity). It is intended to be
> suitable for both debug builds and release builds. [0]

_GLIBCXX_ASSERTIONS was developed not to impact ABI or big-O complexity.

Distros which use this flag include Fedora (2018), Arch Linux (2021) Gentoo Hardened (2022), Alpine (2023), and OpenSUSE [1].

[0] https://bugs.launchpad.net/kicad/+bug/1838448/comments/40
[1] https://github.com/jvoisin/compiler-flags-distro

[Matthias Klose (doko)]

this is added to Fedora's and Gentoo's build systems. No, this definitely not a GCC default setting

[Mark Esler (eslerm)]

Security's request to add gcc hardening flags is valid as discussed in https://bugs.launchpad.net/ubuntu/+source/gcc-12/+bug/1972043.

> As Kees says, adding it to gcc means not only does this benefit Ubuntu archive packages, but also any software which is built on a Ubuntu machine using gcc (ie snaps built by launchpad, packages built on Github using Ubuntu as the CI backend etc) - which is a great benefit IMO.

[Matthias Klose (doko)]

seriously, referencing a bug from 2008 in bluez-utils?

[Mark Esler (eslerm)]

Apologize, I linked the wrong LP. Edited comment to https://bugs.launchpad.net/ubuntu/+source/gcc-12/+bug/1972043

[Mark Esler (eslerm)]

This is being pushed to 24.10