--- a/configure.in
+++ b/configure.in
@@ -93,9 +93,9 @@
   *cygwin*)	V_PCAP_LDLIBS="-lwpcap";
 esac
 
-dnl define _BSD_SOURCE for libc-2
+dnl define _DEFAULT_SOURCE for libc-2
 if [[ -f /lib/libc-2* ]]; then
- V_DEFINES="$V_DEFINES -D_BSD_SOURCE"
+ V_DEFINES="$V_DEFINES -D_DEFAULT_SOURCE"
 fi
 
 AC_SUBST(V_CCOPT)