--- IO-AIO/configure	2008/05/11 01:03:33	1.2
+++ IO-AIO/configure	2008/05/11 19:11:05	1.3
@@ -2754,11 +2754,6 @@
 #define HAVE_READAHEAD 1
 _ACEOF
 
-test $ac_cv_readahead = yes &&
-cat >>confdefs.h <<\_ACEOF
-#define _GNU_SOURCE 1
-_ACEOF
-
 
 { echo "$as_me:$LINENO: checking for fdatasync" >&5
 echo $ECHO_N "checking for fdatasync... $ECHO_C" >&6; }