add the usual extern C silliness to pydtrace.h
diff --git a/Include/pydtrace.h b/Include/pydtrace.h
index 4888606..140d2e1 100644
--- a/Include/pydtrace.h
+++ b/Include/pydtrace.h
@@ -2,6 +2,9 @@
 
 #ifndef Py_DTRACE_H
 #define Py_DTRACE_H
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #ifdef WITH_DTRACE
 
@@ -44,4 +47,7 @@
 
 #endif /* !WITH_DTRACE */
 
+#ifdef __cplusplus
+}
+#endif
 #endif /* !Py_DTRACE_H */