enable thread safety for sbrk and emmalloc, when using WASM_WORKERS

[mannk123]

This is a fix for the issue reported in PR #18171 .

More details in my comment on that PR:
#18171 (comment)

[sbc100]

Combining these into a single block makes sense to me.

Also, perhaps instead of defined(__EMSCRIPTEN_PTHREADS__) || defined(__EMSCRIPTEN_WASM_WORKERS__) you can just use ifdef __EMSCRIPTEN_SHARED_MEMORY__ ? Or equivalently ifdef _REENDTRANT

[juj]

Hmm well, I suppose this could now just read #ifdef __EMSCRIPTEN_SHARED_MEMORY__ everywhere without introducing a RETRY_SBRK define at all?

[mannk123]

Ah, I had thought to keep it for the brevity (since EMSCRIPTEN_SHARED_MEMORY is kind of long), and maybe for future use. Anyway, changed to #ifdef __EMSCRIPTEN_SHARED_MEMORY__ as you suggested.

[juj]

Ohh, good find there were missing shared paths.

I think #ifdef __EMSCRIPTEN_SHARED_MEMORY__ would be good here. That way these call sites will also work in the third build mode, where one is building against shared memory, but without pthreads nor wasm workers.

[mannk123]

Makes sense, changed to use #ifdef EMSCRIPTEN_SHARED_MEMORY .

[juj]

Great, thanks!