Yeah I think your change is enough.

Adding a cast would solve this compiler warning:

Python/random.c:168:17: warning: conversion to ‘int’ from ‘long int’ may alter its value [-Wconversion]
             n = syscall(SYS_getrandom, dest, n, flags);
                 ^

But on the other hand, when I just recompiled Python with -Wconversion, I got hundreds of other warnings, so maybe there is a good reason we don’t enable that warning.