[llvm] [M68k] implement -mxgot (PR #119803)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

Reading GCC's `-mxgot` description, it seems like the problem is not about the address of `_GLOBAL_OFFSET_TABLE_` exceeding 16 bits -- it's the _offset_ that gets over 16 bits. That's why they used an example error message "relocation truncated to fit: R_68K_GOT16O foobar", where `GOT16O` is the offset between the beginning of GOT to the target entry. 

https://github.com/llvm/llvm-project/pull/119803