[clang] [clang-repl] Fix PLT offset too large linker error on ARM (PR #78959)

[Stefan Gränitz via cfe-commits]

weliveindetail wrote:

Oh, I usually don't do that, but it's certainly a valid point. Can you think of a better way to express the condition here? We need `-Wl,--long-plt` for ARM targets whenever the used linker supports it. Otherwise we have to assume that it emits such PLTs by default.

https://github.com/llvm/llvm-project/pull/78959