[libc-commits] [libc] [libc][NFC] rename LONG_DOUBLE_IS_DOUBLE into LIBC_LONG_DOUBLE_IS_DOUBLE (PR #73948)

[Joseph Huber via libc-commits]

jhuber6 wrote:

> Now that I think about it, technically in this case, `long double` and `double` are still 2 different types to the compilers, so `LIBC_LONG_DOUBLE_IS_FLOAT64` should fit better. WDYT?

I agree, since they are distinct types as far as the compiler is concerned, see https://godbolt.org/z/szYf3jYPP for the GPU case.

https://github.com/llvm/llvm-project/pull/73948