[clang] Extension: allow recursive macros (PR #65851)

[Emilia Kond via cfe-commits]

rymiel wrote:

How would you deal with the issue of infinite loops? The following program:

```cpp
#define2 boom(X) boom(X)

boom(0)
```

Will continue to infinitely(?) consume memory until it is killed, either by the user or due to running out of memory on the system

https://github.com/llvm/llvm-project/pull/65851