[clang] [llvm] Implement a subset of builtin_cpu_supports() features (PR #82809)

[Amy Kwan via cfe-commits]

================
@@ -132,6 +132,14 @@ PPC_LNX_CPU("power10",47)
 #ifndef AIX_POWERPC_USE_SYS_CONF
   #define AIX_POWERPC_USE_SYS_CONF
   #define AIX_SYSCON_IMPL_IDX 1
+  #define AIX_SYSCON_CACHE_IDX 5
+  #define AIX_SYSCON_SMT_IDX 44
+  #define AIX_SYSCON_VMX_IDX 46
+  #define AIX_SYSCON_DFP_IDX  53
+
+  #define SC_TM_VER   59
+  #define SC_MMA_VER  62
----------------
amy-kwan wrote:

```suggestion
  #define SYC_CALL_TM_VER   59
  #define SYS_CALL_MMA_VER  62
```
It would be more clear to expand what `SC` is, because it can mean either sys call or sys conf.

https://github.com/llvm/llvm-project/pull/82809