[llvm] [Darwin] Fix availability of exp10 for watchOS, tvOS, xROS. (PR #98542)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `arc-builder` running on `arc-worker` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/1385

Here is the relevant piece of the build log for the reference:
```
Step 5 (build-unified-tree) failure: build (failure)
...
64.726 [5/14/100] Linking CXX shared library lib/libclang.so.19.0.0git
64.731 [4/14/101] Creating library symlink lib/libclang.so.19.0git lib/libclang.so
64.829 [2/15/102] Linking CXX executable bin/c-arcmt-test
64.999 [2/14/103] Linking CXX executable bin/llvm-gsymutil
65.289 [2/13/104] Linking CXX executable bin/llvm-exegesis
65.720 [2/12/105] Linking CXX executable bin/clang-scan-deps
65.726 [2/11/106] Linking CXX executable bin/clang-check
65.921 [2/10/107] Linking CXX executable bin/llvm-isel-fuzzer
66.887 [2/9/108] Linking CXX executable bin/llvm-split
69.680 [2/8/109] Linking CXX executable bin/opt
command timed out: 1200 seconds without output running [b'ninja', b'-j', b'16'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1426.721691

```

https://github.com/llvm/llvm-project/pull/98542