Build fails since ranlib is not ran on the static lib, resulting in no table of contents error

This is fragile: https://github.com/r-lib/webfakes/blob/8685f6ea1c8a8c7c62f08d2ca472186b276324c0/src/Makevars.in#L13-L14
It works on some platforms but fails on others.

Either ranlib should be ran on the archive or flags adjusted to the same effect.