Support no atomics Windows builds with meson

[satk0]

Hello, first of all I am really thankful that you also maintain meson.build file.

I've recently tried to build radare2 with yours meson.build file on windows but it failed with this message:

I think the issue is due to qjs ading /experimental:c11atomics flag even when msvc compiler is not supporting atomics, thus setting _STDC_NO_ATOMICS_ var to false.

quickjs/meson.build

Line 64 in a75498b

'/experimental:c11atomics',

I think the way to fix this is to add with_atomics option to meson_options.txt and to omit the atomics when set to false. Wdyt?

I could take care of that and make a PR if only I got a green light from you ;)

[saghul]

IIRC there was some fox recently that required us to always depend on atomics.

[satk0]

Looking at the error again. I think that the flag is not an issue. quickjs-libc.c is being build for no reason. Looking at the meson-options.txt it should not be built. How is this possible?

[past-due]

IIRC there was some fox recently that required us to always depend on atomics.

What fix would that be? (Beyond the cross-platforms Atomics support added in 569b238 ?)

[saghul]

It happened here: 62fb636

Technically it should still work if you don't build the libc though.

@satk0 sorry I'm not familiar enough with Meson myself. If you are not using libc it should indeed not be compiled and then you might be able to compile the core library with that old MSVC version. Side question: any reason why you can't use a more modern MSVC?

[satk0]

No problem, I decided to use our own crafted meson.build but the building still fails for windows. I update qjs rn for r2 and windows things is driving me mad.

About MSVC version - I honestly don't know. @trufae could definitely explain it

[past-due]

It happened here: 62fb636

Technically it should still work if you don't build the libc though.

Ah, thank you for the link! Yep, that would be why we didn’t hit it as an issue (we don’t build the libc).