[PATCH] Remove support for runtime multithreading

[Chandler Carruth]

One more thing to split out, and I think this will actually look good.

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Comment at: lib/Support/ManagedStatic.cpp:27
@@ -25,3 +26,3 @@
   if (llvm_is_multithreaded()) {
-    llvm_acquire_global_lock();
+    llvm::MutexGuard Lock(llvm_get_global_lock());
 
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This (and the related change to the interface) is the other unrelated cleanup that I would like to see separated out from the change which has policy effect.

Consider, if we need to revert the runtime control of multithreading for a brief period because something breaks, we shouldn't also lose this cleanup change.

http://reviews.llvm.org/D4139