Revert "Revert "Revert 220932.": "Removing the static initializer in ManagedStatic.cpp by using llvm_call_once to initialize the ManagedStatic mutex""

This reverts commit r269577.
Broke NetBSD, waiting for Kamil to investigate

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 269584

1 files changed, 0 insertions, 24 deletions

diff --git a/llvm/lib/Support/Windows/Threading.inc b/llvm/lib/Support/Windows/Threading.inc
deleted file mode 100644
index 196be890dbf..00000000000
--- a/llvm/lib/Support/Windows/Threading.inc
+++ /dev/null
@@ -1,24 +0,0 @@
- #include <windows.h>
-
-#ifdef MemoryFence
-// WinNT.h seems to define a MemoryFence macro.
-#undef MemoryFence
-#endif
-
-void llvm::call_once(once_flag &flag, void (*fptr)(void)) {
-  while (flag != Done) {
-    if (flag == Wait) {
-      ::Sleep(1);
-      continue;
-    }
-
-    sys::cas_flag old_val = sys::CompareAndSwap(&flag, Wait, Uninitialized);
-    if (old_val == Uninitialized) {
-      fptr();
-      sys::MemoryFence();
-      flag = Done;
-      return;
-    }
-  }
-  sys::MemoryFence();
-}