diff -up plruby-0.5.3/src/plruby.h.debug plruby-0.5.3/src/plruby.h
--- plruby-0.5.3/src/plruby.h.debug	2007-12-26 16:58:02.000000000 +0100
+++ plruby-0.5.3/src/plruby.h	2012-02-15 17:17:32.650551398 +0100
@@ -2,6 +2,8 @@
 #include <fcntl.h>
 #include <setjmp.h>
 
+#include "postgres.h"
+
 #include "executor/spi.h"
 #include "commands/trigger.h"
 #include "utils/elog.h"