Avoid depending on Julia-patched libunwind ABI

[gbaraldi]

I'm slightly worried about using the exe handle here. I wonder I should instead do a specific dlopen of libunwind.

[topolarity]

I'm slightly worried about using the exe handle here. I wonder I should instead do a specific dlopen of libunwind.

Yeah, I don't think this will work as-is on Windows.

[gbaraldi]

This already doesn't work on windows (it's behind an ifdef)

[xal-0]

With #58815, using the exe handle may or may not be the right choice depending on the intended behaviour. If we specifically want a version of libuwind depended on by libjulia-internal, we'd need no_deps=0 on the call to jl_dlsym. If we want to search for system libraries using the default search order, we should use jl_RTLD_DEFAULT_handle.

[gbaraldi]

Well, I guess we would want to fallback to whatever libjulia-internal thinks libunwind is

[gbaraldi]

Should this be changed when you dlfind changes?

[xal-0]

Should this be changed when you dlfind changes?

Yes, but it'll just require adding a 0 argument, which I will handle when merging.

[topolarity]

@gbaraldi did you want this backported to 1.12?