[libc++abi] Delete config.h

Summary: It's now completely empty, so we can remove it entirely.

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D31502

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@299129 91177308-0d34-0410-b5e6-96231b3b80d8
10 files changed