[compiler-rt] Found one more delta to unbreak build for z/os (PR #82789)

[Sean Perry via llvm-commits]

================
@@ -368,10 +368,11 @@ static __inline fp_t __compiler_rt_fmax(fp_t x, fp_t y) {
 #endif
 }
 
-#elif defined(QUAD_PRECISION) && defined(CRT_HAS_TF_MODE)
+#elif defined(QUAD_PRECISION)
+#if defined(CRT_HAS_TF_MODE)
+#if defined(CRT_HAS_IEEE_TF)
----------------
perry-ca wrote:

I tried out your proposed structure, and it works for z/OS.  I'll make the change.  Shall I change this:
```
#else
#error Unsupported TF mode type
```
The condition isn't entirely correct anymore since the `CRT_LDBL_128BIT` case wasn't a TF mode.  The if/elif chain handles more than just the different TF modes.

If so, any suggestions?

https://github.com/llvm/llvm-project/pull/82789