[flang-commits] [flang] [flang] Allow derf as alternate spelling for erf (PR #95784)

[Paul Osmialowski via flang-commits]

pawosm-arm wrote:

> DERF is mentioned as a specific name extension of ERF for argument and return type Real(kind=8). https://gcc.gnu.org/onlinedocs/gfortran/ERF.html
> 
> Is the usage in wrf and other codes you saw an alias of ERF for all Real kinds or specifically for Real(kind=8)?

NB, it must match the type of other `D`-prefixed intrinsics as it is used in an expression like this one:

```
(1.-DERF(5.D+0/DSQRT(2.D+0)))*0.5
```

https://github.com/llvm/llvm-project/pull/95784