Fix linking issue after r241271 (dbghelp.lib was removed from default dependencies on Windows)

llvm-svn: 241278
diff --git a/lldb/source/Core/Mangled.cpp b/lldb/source/Core/Mangled.cpp
index 00a90a7..3e1a8bb 100644
--- a/lldb/source/Core/Mangled.cpp
+++ b/lldb/source/Core/Mangled.cpp
@@ -13,6 +13,7 @@
 #if defined(_MSC_VER)
 #include "lldb/Host/windows/windows.h"
 #include <Dbghelp.h>
+#pragma comment(lib, "dbghelp.lib")
 #define LLDB_USE_BUILTIN_DEMANGLER
 #elif defined (__FreeBSD__)
 #define LLDB_USE_BUILTIN_DEMANGLER