src: fix ignore GCC -Wcast-function-type for older compilers

Fixes: https://github.com/nodejs/node/issues/31517

PR-URL: https://github.com/nodejs/node/pull/31524


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>