diff --git a/configure.in b/configure.in
index d281c7d..33b8289 100644
--- a/configure.in
+++ b/configure.in
@@ -169,6 +169,7 @@
 	LIBS="$LIBS -lgen -lsocket"
 	;;
 *-*-sco3*)
+	AC_DEFINE(USE_PIPES)
 	CFLAGS="$CFLAGS -I/usr/local/include"
 	LDFLAGS="$LDFLAGS -L/usr/local/lib"
 	MANTYPE='$(CATMAN)'