Enable stack cookies for C speedups about markupsafe

[ThiefMaster]

-fstack-protector-all - All functions use stack cookies.
-fstack-protector-strong - Functions use stack cookies if they have arrays on the stack, take memory references to their own stack variables, call alloca(), or use variable-length arrays (VLA).

Apparently these compiler switches enable them. But I guess they'd need to be specified in a compiler-agnostic way since the speedups may be compiled e.g. with microsoft's compiler if someone is on windows.

[ThiefMaster]

If they cannot be enabled with a compiler flag, #pragma or some other preprocessor directive this sounds more like something setuptools would have to do (as all we do to build the speedups extension is this)

[methane]

Can't you use just CFLAGS=-fstack-protect-all?
Use it by default is not common practice on Python, and it makes this library less portable.

[davidism]

I'm not convinced this is a good idea. I looked at a few other projects and none of them had these flags set, including SQLAlchemy and Cryptography, two widely used libraries with C components. Is MarkupSafe the only package that raised this warning? Re: portability, will this affect wheels I build and release to PyPI? Does setting that env var and telling pip to build from source accomplish what you need? Without understanding this more, I'm not planning on implementing it.

[davidism]

Closing due to lack of information. If this is important to you, I'll need help to understand and implement it correctly.