Sure. But it's not the same thing (instead of invoking the command once it invokes a command multiple times) and a workaround at best. And ergonomics are not great. Especially if you first type the command without xargs, and then find out the argument list is too long and you'll have to reformulate it but now with xargs.

How does that help with a GCC command line?

The ARGS_MAX (`getconf ARGS_MAX`) is defined at the OS level (glibc maybe? haven't looked); xargs will also be subject to it's limitation like all other processes. One can use:

    xargs --show-limits --no-run-if-empty </dev/null

...to see a nicely formatted output include the -2048 POSIX recommendation on a separate line.