Concatenate strings at compile time.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@193384 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF] Handle edge case where no section alignment is specified.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@193385 91177308-0d34-0410-b5e6-96231b3b80d8