[llvm] [Object][x86-64] Add support for `R_X86_64_GLOB_DAT` relocations. (PR #103029)

[Alastair Houghton via llvm-commits]

al45tair wrote:

OK, I _think_, talking to other folks, that we're probably going to go down the fix-it-in-Swift route instead of this, so we can probably merge the revert PR (#103497).

https://github.com/llvm/llvm-project/pull/103029