--- rxvt-unicode/autoconf/configure.in	2004/12/01 02:33:32	1.41
+++ rxvt-unicode/autoconf/configure.in	2004/12/20 16:47:14	1.42
@@ -42,7 +42,7 @@
 fi
 AC_SUBST(LINKER,[$LINKER])
 
-CPPFLAGS="-D_GNU_SOURCE -D_XOPEN_SOURCE"
+CPPFLAGS="-D_GNU_SOURCE -D_XOPEN_SOURCE=2"
 
 dnl if test x$GXX = xyes; then
 dnl    CXXFLAGS="$CXXFLAGS" dnl I once had -fno-exceptions, but I am using them now...