[clang] [Sparc][clang] make `_Complex` ABI GCC-compatible (PR #212340)

[Sergei Barannikov via cfe-commits]

https://github.com/s-barannikov commented:

I'm not sure we need `-fclang-abi-compat` flag, but I'm not an interested party.
@rorth @brad0 

Also, are _Complex types passed in memory the same way? (when we'are out of argument registers)


https://github.com/llvm/llvm-project/pull/212340