Allow changing the `ar` binary

Make use of setrlimit conditional on ABC_NO_RLIMIT

Gia_ManDupPermFlop to behave as Gia_ManDupPerm

This is useful for cross-compilation, when build `ar` cannot handle
the target object files.

The invocation of `ranlib` is replaced with `ar s`, which is
equivalent and simplifies the build system a bit.

This is useful for POSIX-like platforms that do not have rlimit,
such as WASI.