Unconfuse coverity when it sees the systemd headers

src/or/main.c

@@ -76,6 +76,12 @@
 #endif
 
 #ifdef HAVE_SYSTEMD
+#   if defined(__COVERITY__) && !defined(__INCLUDE_LEVEL__)
+/* Systemd's use of gcc's __INCLUDE_LEVEL__ extension macro appears to confuse
+ * Coverity. Here's a kludge to unconfuse it.
+ */
+#   define __INCLUDE_LEVEL__ 2
+#   endif
 #include <systemd/sd-daemon.h>
 #endif