Meson: Enable NDEBUG by default in release builds?

[jhasse]

1896 adds a new option for b_ndebug that would automatically define it for release builds. There's also some discussion if this should just be the default, but the PR doesn't touch that, so I thought that discussion could be continued in its own issue.

Summary:

• It's also what CMake does
• NDEBUG is a C/C++ standard
• Would make #1896 obsolete (or build upon it)
• Some distros don't like it enabled by default; why?

[polarina]

I'd imagine most distros use the plain build type and specify their own build flags. Changing the default behaviour of release builds thus shouldn't affect them.

[nirbheek]

I would be in favour of this.

[SoapGentoo]

This changes what most people would expect, namely that _release_ binaries don't contain any assert()s anymore, so I am very much in favour of this too.

[phillipjohnston]

Except... there are many people who also keep assert() enabled in release builds.

[phillipjohnston]

I guess, however, I fall into the "plain" camp and pick my own flags in this case.