use 64-bit types instead of off_t/size_t to avoid the issue when

use 64-bit types instead of off_t/size_t to avoid the issue when
gold plugin is built with Large File Support (sizeof(off_t) == 64 on i686)
and the rest of LLVM is built w/o Large File Support
(sizeof(off_t) == 32 on i686) which corrupts the stack.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139873 91177308-0d34-0410-b5e6-96231b3b80d8