[llvm] [clang] [PowerPC][X86] Make cpu id builtins target independent and lower for PPC (PR #68919)

[via cfe-commits]

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@@ -0,0 +1,80 @@
+#ifndef PPC_FEATURE
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diggerlin wrote:

we will support these feature in AIX OS soon.
can we change `PPC_FEATURE` to `PPC_LINUX_FEATURE`

and `PPC_CPU` to `PPC_LINUX_CPU` 

and when implement the __builtin_cpu_is and __builtin_cpu_supports in AIX OD

we can `PPC_AIX_FEATURE` and `PPC_AIX_CPU`

https://github.com/llvm/llvm-project/pull/68919