[libunwind] Provide placement new definition

While Clang automatically generates the code for placement new,
g++ doesn't do that so we need to provide our own definition.

Differential Revision: https://reviews.llvm.org/D57455

git-svn-id: https://llvm.org/svn/llvm-project/libunwind/trunk@352966 91177308-0d34-0410-b5e6-96231b3b80d8

src/UnwindCursor.hpp

diff --git a/src/UnwindCursor.hpp b/src/UnwindCursor.hpp
index a830d58..406f229 100644
--- a/src/UnwindCursor.hpp
+++ b/src/UnwindCursor.hpp
@@ -894,6 +894,10 @@
   virtual void        saveVFPAsX();
 #endif
 
+  // libunwind does not and should not depend on C++ library which means that we
+  // need our own defition of inline placement new.
+  static void *operator new(size_t, UnwindCursor<A, R> *p) { return p; }
+
 private:
 
 #if defined(_LIBUNWIND_ARM_EHABI)