[llvm] r186934 - Add an initial implementation of archive symbol table generation.

[Rafael Espíndola]

> As a point of reference, BSD ar currently refuses to create an archive
> with a large UID, reporting "ar: fatal: Numeric user ID too large"

Do you know why? The UID is not really used. In fact, in my TODO list
I have implementing the 'D' (deterministic) modifier and probably
making it the default.

Cheers,
Rafael