Move the function and data section flags into the options struct and
make the functions to set them non-static.
Move and rename the llvm specific backend options to avoid conflicting
with the clang option.

Paired with a backend commit to update.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209238 91177308-0d34-0410-b5e6-96231b3b80d8