Add C++ wrapper.

(Logical change 1.70)
diff --git a/include/libunwind-hppa.h b/include/libunwind-hppa.h
index aa493f9..c2f00f1 100644
--- a/include/libunwind-hppa.h
+++ b/include/libunwind-hppa.h
@@ -26,6 +26,10 @@
 #ifndef LIBUNWIND_H
 #define LIBUNWIND_H
 
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
 #include <inttypes.h>
 #include <ucontext.h>
 
@@ -83,4 +87,8 @@
 
 #include "libunwind-common.h"
 
+#if defined(__cplusplus) || defined(c_plusplus)
+}
+#endif
+
 #endif /* LIBUNWIND_H */