*

* In src/engine/engine_crossplatform.h add a conditional block specifically for Emscripten within the preprocessor directive in the engine_crossplatform.h file. Inside this block, include the sort_r.h header and define the mjQUICKSORT and quicksortfunc macros appropriately. This will separate the handling for Apple, Emscripten, and other platforms.

Also, for example in mjxmacro.h you have to involve adding explicit casting to size_t for the calculations of key_mpos and key_mquat array sizes, ensuring correct memory allocation and preventing potential integer overflow issues.