The makefile build system had two lists of the 32-bit runtime libraries
to build and one had grown out of sync. Put this list in a variable so
this doesn't happen again.

The whole thing here is somewhat suspicious as we don't support 32-bit
environments with a 64-bit bi-arch capable compiler, but none have
complained yet about this so I'm just leaving it alone.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@184665 91177308-0d34-0410-b5e6-96231b3b80d8