[libunwind] Avoid using C++ headers.

This is useful for building libunwind on libcxx-free systems.

llvm-svn: 321440
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 91e49066e3067bcc585c434490ba73aef1c3988e
diff --git a/src/DwarfParser.hpp b/src/DwarfParser.hpp
index 95af7a6..330dadd 100644
--- a/src/DwarfParser.hpp
+++ b/src/DwarfParser.hpp
@@ -17,7 +17,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <limits>
+#include <limits.h>
 
 #include "libunwind.h"
 #include "dwarf2.h"