[wasm][wasi] No main function should be required when building a library

[silesmo]

Description

Currently mono requires a main function when building for wasi. This shouldn't be required.

Related: #96419

@AaronRobinsonMSFT @lewing @yowl @jsturtevant

Reproduction Steps

Try to build example with main removed.
Example: https://github.com/silesmo/wasm-unmanaged-callers-bug/blob/main/mono-example/MonoEntrypoint.cs

Expected behavior

No main function should be required for a library.

Actual behavior

Main function is required.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

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Issue Details

---

Description

Currently mono requires a main function when building for wasi. This shouldn't be required.

Related: #96419

@AaronRobinsonMSFT @lewing @yowl @jsturtevant

Reproduction Steps

Try to build example with main removed.
Example: https://github.com/silesmo/wasm-unmanaged-callers-bug/blob/main/mono-example/MonoEntrypoint.cs

Expected behavior

No main function should be required for a library.

Actual behavior

Main function is required.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

Author:	silesmo
Assignees:	-
Labels:	arch-wasm, untriaged, area-Build-mono, os-wasi
Milestone:	-

[maraf]

Similar requirement tracked for browser in #77191

[lewing]

See the notes https://github.com/dotnet/runtimelab/blob/feature/NativeAOT-LLVM/src/coreclr/nativeaot/Bootstrap/main.cpp#L179-L229
and some background here https://dylibso.com/blog/wasi-command-reactor/
cc @pavelsavara