IPO: Avoid brace initialization of a map, some versions of libc++ don't like it

Should fix the build failure on these darwin bots:

http://lab.llvm.org:8080/green/job/clang-stage1-cmake-RA-incremental_build/12427/
http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_build/10389/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242945 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed