$OpenBSD: patch-configure,v 1.4 2016/03/18 19:01:04 jca Exp $
--- configure.orig	Thu Apr 13 15:37:26 2000
+++ configure	Fri Mar 18 19:55:55 2016
@@ -1035,7 +1035,7 @@ ac_link='${CC-cc} -o conftest${ac_exeext} $CFLAGS $CPP
 cross_compiling=$ac_cv_prog_cc_cross
 
 
-CFLAGS="$CFLAGS -D_BSD_SOURCE -D_POSIX_SOURCE=199506L"
+CFLAGS="$CFLAGS -D_BSD_SOURCE -D_POSIX_C_SOURCE=199506L"
 
 if test x$GCC = xyes; then
   CFLAGS="$CFLAGS -Wall -ansi -pedantic"
