Duplicate symbol error when compiling rust-onig to wasm

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I'm trying to compile rust-onig to wasm and I'm running into issues. I'm creating a markdown to html plugin library using wasm, and I want to utilize rust-onig for its performance benefits. I've already successfully built a version of the library using pulldown-cmark, syntect, and ammonia, but I want to try using rust-onig instead because it's supposed to be faster.

When I build with cargo build --lib --release, everything works fine, but when I add --target wasm32-unknown-unknown, I start getting errors. I've managed to work around the missing <stdlib.h> errors by including the relevant libc headers from the emscripten source. However, I'm now getting a new error about duplicate symbols of OnigEncodingASCII, etc. in the object files regexec.o and regerror.o.

I've checked the object files at target/wasm32-unknown-unknown/release/build/onig_sys*/out with wasm-objdump -x, and sure enough, the symbols are duplicated. I'm supplying rustflags = ['-Z', 'wasm-c-abi=spec']. I've also tried building with the wasm32-unknown-emscripten target, but I get the same error.

I've tried using Clang as the linker, so that wasm-ld is used, but I get the same error. I've also found some potential solutions online, such as passing --redefine-sym to objcopy, but I don't know how to use that flag. Another solution I found was using --disable-shared, but I don't know how to use that flag either.

Can anyone help me resolve this issue? I'm a newbie, so please let me know if I'm making some rookie mistake.

Specifically, I have three questions:

  1. Why is this happening, especially on the wasm target/with wasm-bindgen?
  2. How can I ignore or resolve this issue? Can I use --redefine-sym by objcopy, and if so, how do I pass this argument via Cargo.toml/config.toml?
  3. Is there anything else I can try to resolve this issue?