Changes to ghc

Changes to ghc:
commit 619fd18de0700edb531db5f3836b034489460b88
Author: Austin Seipp <austin@well-typed.com>
Date:   Sat Oct 26 12:50:16 2013 -0500

    Fix getPhysicalMemorySize on OS X (#8481)

    Darwin doesn't support _SC_PHYS_PAGES, but we can get the exact number
    of bytes of physical memory via 'hw.memsize', so we use that instead.

    Signed-off-by: Austin Seipp <austin@well-typed.com>