msvcr110: Add _Lock_shared_ptr_spin_lock implementation.

dlls/msvcr110/msvcr110.spec

@@ -854,7 +854,7 @@
 @ cdecl _Gettnames()
 @ extern _HUGE MSVCRT__HUGE
 @ cdecl _IsExceptionObjectToBeDestroyed(ptr)
-@ stub _Lock_shared_ptr_spin_lock
+@ cdecl _Lock_shared_ptr_spin_lock()
 @ stub -arch=i386 _NLG_Dispatch2
 @ stub -arch=arm,win64 __NLG_Dispatch2
 @ stub -arch=i386 _NLG_Return
@@ -863,7 +863,7 @@
 @ stub -arch=win64 _SetImageBase
 @ stub -arch=win64 _SetThrowImageBase
 @ cdecl _Strftime(str long str ptr ptr)
-@ stub _Unlock_shared_ptr_spin_lock
+@ cdecl _Unlock_shared_ptr_spin_lock()
 @ cdecl _W_Getdays()
 @ cdecl _W_Getmonths()
 @ cdecl _W_Gettnames()

dlls/msvcrt/lock.c

@@ -1018,6 +1018,27 @@ MSVCRT_bool __thiscall _ReentrantBlockingLock__TryAcquire(_ReentrantBlockingLock
 }
 #endif
 
+#if _MSVCR_VER == 110
+static LONG shared_ptr_lock;
+
+void __cdecl _Lock_shared_ptr_spin_lock(void)
+{
+    LONG l = 0;
+
+    while(InterlockedCompareExchange(&shared_ptr_lock, 1, 0) != 0) {
+        if(l++ == 1000) {
+            Sleep(0);
+            l = 0;
+        }
+    }
+}
+
+void __cdecl _Unlock_shared_ptr_spin_lock(void)
+{
+    shared_ptr_lock = 0;
+}
+#endif
+
 /**********************************************************************
  *     msvcrt_free_locks (internal)
  *