Arch Linux

I tried to work this around by defining the environment variable `EMMAKEN_CFLAGS='-Wno-unknown-warning-option'`. Compilation resumed until it failed to find `unwind.h` for `libc++abi-noexcept.a`. Again, I worked this around by copying it from `/usr/include/` to `/usr/lib/emscripten/system/include/`. Then the python script crashed:

```
Traceback (most recent call last):
File "/usr/lib/emscripten/emcc.py", line 3652, in <module>
sys.exit(run(sys.argv))
File "/usr/lib/emscripten/emcc.py", line 2205, in run
final = do_emscripten(final, target + '.mem', js_libraries)
File "/usr/lib/emscripten/emcc.py", line 452, in do_emscripten
emscripten.run(infile, outfile, memfile, js_libraries)
File "/usr/lib/emscripten/emscripten.py", line 2723, in run
shared.Settings.STRUCT_INFO = shared.Cache.get(generated_struct_info_name, generate_struct_info)
File "/usr/lib/emscripten/tools/cache.py", line 133, in get
temp = creator()
File "/usr/lib/emscripten/emscripten.py", line 2720, in generate_struct_info
gen_struct_info.main(['-q', '-c', '-o', out])
File "/usr/lib/emscripten/tools/gen_struct_info.py", line 556, in main
struct_info = inspect_code(header_files, cpp_opts, structs, defines)
File "/usr/lib/emscripten/tools/gen_struct_info.py", line 420, in inspect_code
info = shared.run_js(js_file[1]).splitlines()
File "/usr/lib/emscripten/tools/shared.py", line 1057, in run_js
engine = JS_ENGINES[0]
IndexError: list index out of range
```

So, it seems like this package needs more testing.

Worked around it with these changes (as in the patch):

- Remove the "-Wno-int-in-bool-context" flag.
- Turn off "-Werror" when building system libs.
- Add include path "/usr/lib/emscripten/system/lib/libunwind/include" when building libcxxabi.
- Add "node" as the default JS engine.

This is really weird. Can you guys report this upstream?

Well, what we said were all workarounds. The upstream binary
distribution (emsdk install latest-upstream) works all fine.
And it bundles with clang 10.0.

As for the JS_ENGINES, when using "emsdk activate latest-upstream",
the "~/.emscripten" will have an entry to set JS_ENGINES to the
bundled nodejs.

LLVM commit SHAs should be fetched from https://chromium.googlesource.com/emscripten-releases/+/refs/heads/master/DEPS
e.g. currently it's 9ecacb0d54fb89dc7e6da66d9ecae934ca5c01d4.

Thanks for the hint. Check rel -2.

No more warnings about LLVM versions, but still doesn't work, complaining:

1. cannot find "unwind.h"
2. list index out of range in "JS_ENGINES[0]"

where,

1. can be fixed by the attached patch (which should probably report to upstream). But the emsdk version do not need this change, strange.

2. can be fixed by adding this to prepare() in PKGBUILD to uncomment JS_ENGINES line in settings template:

sed -i 's|^#\s*\(JS_ENGINES\s*=\)|\1|' tools/settings_template_readonly.py

Ok, thanks. Try rel -3.

Can you post your patch upstream?

After looking deeper into it, I now know why it cannot find "unwind.h".

The emsdk version has bundled lib/clang/10.0.0/include which has unwind.h.
This emscripten package did not bundle that, and the Arch's clang is 8.0.1,
which has only /usr/lib/clang/8.0.1/include.

My patch asks libcxxabi to include the Emscripten-bundled libunwind,
which has unwind.h, but is not exactly the same as the clang's unwind.h.

I think this is still our packaging problem. We should probably:

- Put LLVM binaries into /usr/lib/emscripten-llvm/bin/
- Copy LLVM and clang headers into
/usr/lib/emscripten-llvm/lib/clang/10.0.0/include/
/usr/lib/emscripten-llvm/include/clang-c/
/usr/lib/emscripten-llvm/include/llvm-c/
- Compile clang with some option to look /usr/lib/emscripten-llvm/lib/clang/10.0.0/include/ and such for extra system headers.
- Remember to modify LLVM_ROOT in settings_template_readonly.py.

rel -3 got LLVM_ROOT wrong.
https://git.archlinux.org/svntogit/community.git/tree/trunk/arch-template.patch?h=packages/emscripten#n13
should be
+LLVM_ROOT = "/usr/lib/emscripten-llvm"

Except for that, it works.

Sorry, fixed. Please check.

rel -4 works.

But like I said, we should probably bundle lib/clang/10.0.0/include somehow like what the emsdk distribution does.
My libcxxabi-include-libunwind.patch was just a workaround to not bundling this.

I'm not sure where those files would be coming from. It seems lib/clang/10.0.0/include is actually llvm-project/clang/lib/Headers? Then, where in the package should this end up at? There is /usr/lib/emscripten/system/include/ but then what would the final path be?

It's a bit confusing, really.

Would be amazing if you could spend the time to make a patch for this to make it more like the emscripten-sdk (which I assume is more correct).