WASM/emscripten builds crash in cfg_free() — libconfuse cfg_yylex_destroy signature mismatch #1436

Summary

OpenOMF cross-compiled to WebAssembly (via the openomf-web port) traps at startup inside cfg_free() whenever a mod manifest is parsed. Root cause is a return-type mismatch in the vendored libconfuse dependency, not OpenOMF code.

Root cause

libconfuse ships:

// src/confuse.c
extern void cfg_yylex_destroy(void);   // declaration
...
cfg_yylex_destroy();                   // called from cfg_free()

but the flex-generated lexer defines it as:

// generated lexer (flex >= 2.6)
int yylex_destroy(void)

On native ABIs the mismatched return type is harmless. On WebAssembly the runtime enforces exact signatures, so the call traps (RuntimeError: unreachable). Every modmanager manifest parse hits this during engine_init(), so the game never reaches the main menu.

Reproduction

WASM build with any .zip mod present under data/mods/. Startup log stops at:

Found 6 system mods.
Found 0 user mods.
RuntimeError: unreachable

Fix

Upstream libconfuse PR aligns the declaration with the generated definition:

• confuse.c: declare cfg_yylex_destroy() as int to match flex output libconfuse/libconfuse#188

Until it lands upstream, Emscripten builds need a local patch:

- extern void cfg_yylex_destroy(void);
+ extern int  cfg_yylex_destroy(void);

Notes for this repo

• Mod support (0.8.6+) relies on cfg_parse_buf/cfg_free, so any future web/emscripten CI is affected.
• The mismatch is also flagged as a wasm-ld: warning: function signature mismatch: cfg_yylex_destroy at link time — a good canary for CI.