[Driver] Add PIE support on Solaris

`clang` currently lacks PIE support on Solaris.  This patch fixes this,
also linking with `crtbeginS.o` and `crtendS.o` for `-pie` and `-shared`.

Tested on `amd64-pc-solaris2.11`, `sparcv9-sun-solaris2.11`, and
`x86_64-pc-linux-gnu`.

Differential Revision: https://reviews.llvm.org/D158206