[PATCH] [Driver] Support -muclibc / -mglibc command line options

[Simon Atanasyan]

The patch you can download from the Phabricator site using the "Download Raw Diff" link is reduced. Probably it is the Phabricator's bug. This file does not contain any new `.o` files. This page has paths like `test/Driver/Inputs/mips_cs_tree/lib/gcc/mips-linux-gnu/4.6.3/uclibc/soft-float/crtbegin.o`. The D4790.diff does not have such files.

I create another patch and attach it to this message.{F129952}

http://reviews.llvm.org/D4790