diff --git a/sysa/gawk-3.0.4/mk/main.mk b/sysa/gawk-3.0.4/mk/main.mk
index 1b47401..ec3d217 100644
--- a/sysa/gawk-3.0.4/mk/main.mk
+++ b/sysa/gawk-3.0.4/mk/main.mk
@@ -32,7 +32,8 @@ CFLAGS = -I vms \
          -DHAVE_STRING_H=1 \
          -DHAVE_STRTOD=1 \
          -DHAVE_SYS_PARAM_H=1 \
-         -DHAVE_UNISTD_H=1
+         -DHAVE_UNISTD_H=1 \
+         -DBITOPS=1
 
 .PHONY: all