When a BL/BLX references a symbol in the same translation unit that is
out of range, use an external relocation. The linker will use this to
generate a branch island rather than a direct reference, allowing the
relocation to resolve correctly.
rdar://12359919
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164615 91177308-0d34-0410-b5e6-96231b3b80d8