Use rb_errinfo() instead of ruby_errinfo for Ruby 1.9

configure.in

@@ -673,6 +673,7 @@ if test x$dumm = xtrue; then
 		[AC_MSG_RESULT([$LIBS]); RUBYLIB=$LIBS],
 		[AC_MSG_ERROR([not found])])
 	AC_SUBST(RUBYLIB)
+	AC_CHECK_FUNCS(rb_errinfo)
 	LIBS=$saved_LIBS
 fi
 

src/dumm/irdumm.c

@@ -21,6 +21,10 @@
 #undef PACKAGE_URL
 #include <ruby.h>
 
+#ifdef HAVE_RB_ERRINFO
+#define ruby_errinfo rb_errinfo()
+#endif
+
 /**
  * main routine, parses args and reads from console
  */