Ruby

Fix malloc_trim on emscripten

gc.c:9746:5: error: implicit declaration of function 'malloc_trim' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
    malloc_trim(0);
    ^

http://rubyci.s3.amazonaws.com/crossruby/crossruby-master-wasm32_emscripten/log/20230916T104311Z.fail.html.gz