`compiler-rt/lib/builtins/divtc3.c` and `multc3.c` don't compile on
Solaris/sparcv9 with `gcc -m32`:
```
FAILED: projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-sparc.dir/divtc3.c.o
[...]
compiler-rt/lib/builtins/divtc3.c: In function ‘__divtc3’:
compiler-rt/lib/builtins/divtc3.c:22:18: error: implicit declaration of function ‘__compiler_rt_logbtf’ [-Wimplicit-function-declaration]
22 | fp_t __logbw = __compiler_rt_logbtf(
| ^~~~~~~~~~~~~~~~~~~~
```
and many more. It turns out that while the definition of `__divtc3` is
guarded with `CRT_HAS_F128`, the `__compiler_rt_logbtf` and other
declarations use `CRT_HAS_128BIT && CRT_HAS_F128` as guard. This only
shows up with `gcc` since, as documented in Issue #41838, `clang`
violates the SPARC psABI in not using 128-bit `long double`, so this
code path isn't used.
Fixed by changing the guards to match.
Tested on `sparcv9-sun-solaris2.11`.
(cherry picked from commit
63a7786111c501920afc4cc27a4633f76cdaf803)