[clang] Fix name conflict with sys/mac.h on AIX

Fixes clang-ppc64-aix bot failure after llvm#88559 (0a6f6df) https://lab.llvm.org/buildbot/#/builders/214/builds/11887

Author: Endilll

clang/include/clang/Basic/Cuda.h

@@ -50,6 +50,11 @@ const char *CudaVersionToString(CudaVersion V);
 // Input is "Major.Minor"
 CudaVersion CudaStringToVersion(const llvm::Twine &S);
 
+// We have a name conflict with sys/mac.h on AIX
+#ifdef _AIX
+#undef SM_32
+#endif
+
 enum class CudaArch {
   UNUSED,
   UNKNOWN,