Update prebuilt Clang to r365631c1 from Android.

The version we had was segfaulting.

Bug: 132420445
Change-Id: Icb45a6fe0b4e2166f7895e669df1157cec9fb4e0
diff --git a/linux-x64/clang/include/llvm/Support/Threading.h b/linux-x64/clang/include/llvm/Support/Threading.h
index 23b115f..46d413d 100644
--- a/linux-x64/clang/include/llvm/Support/Threading.h
+++ b/linux-x64/clang/include/llvm/Support/Threading.h
@@ -32,6 +32,9 @@
 // implementations like libstdc++ are known to have problems on NetBSD,
 // OpenBSD and PowerPC.
 #define LLVM_THREADING_USE_STD_CALL_ONCE 1
+#elif defined(LLVM_ON_UNIX) &&                                                 \
+    ((defined(__ppc__) || defined(__PPC__)) && defined(__LITTLE_ENDIAN__))
+#define LLVM_THREADING_USE_STD_CALL_ONCE 1
 #else
 #define LLVM_THREADING_USE_STD_CALL_ONCE 0
 #endif
@@ -164,6 +167,19 @@
   /// purposes, and as with setting a thread's name no indication of whether
   /// the operation succeeded or failed is returned.
   void get_thread_name(SmallVectorImpl<char> &Name);
+
+  enum class ThreadPriority {
+    Background = 0,
+    Default = 1,
+  };
+  /// If priority is Background tries to lower current threads priority such
+  /// that it does not affect foreground tasks significantly. Can be used for
+  /// long-running, latency-insensitive tasks to make sure cpu is not hogged by
+  /// this task.
+  /// If the priority is default tries to restore current threads priority to
+  /// default scheduling priority.
+  enum class SetThreadPriorityResult { FAILURE, SUCCESS };
+  SetThreadPriorityResult set_thread_priority(ThreadPriority Priority);
 }
 
 #endif