[libc] Add an optional `NAME` argument to `add_entrypoint_object` rule.

This argument can be used to specify the entrypoint name if it is different
from the target name.

Reviewers: gchatelet, abrachet

Differential Revision: https://reviews.llvm.org/D74948

GitOrigin-RevId: cab6ac2612b5e4f22fca357a2c0740bc1b995e96
1 file changed