Align to the large page size (known as a superpage or huge page).
FreeBSD automatically promotes large, superpage-aligned allocations.
Differential Revision: https://reviews.llvm.org/D27042
llvm-svn: 287782
They don't count for the memory or file size, so this is mostly just a
simplification.
The only noticeable difference should be fewer empty program headers.
llvm-svn: 260465