diff --git a/sys/unix/hints/linux.2020 b/sys/unix/hints/linux.2020
index b9119d5c0..16941cbf7 100755
--- a/sys/unix/hints/linux.2020
+++ b/sys/unix/hints/linux.2020
@@ -228,7 +228,7 @@ ifdef WANT_LIBNH
 libnethack.a: $(HOBJ) $(LIBNHSYSOBJ) ../lib/lua/liblua.a
 	$(AR) rcs $@ $(HOBJ) $(LIBNHSYSOBJ) ../lib/lua/liblua.a
 	@echo "$@ built."
-libnethackmain.o : ../sys/lib/libnethackmain.c $(HACK_H)
+libnethackmain.o : ../sys/lib/libnethackmain.c $(HACK_H) ../include/date.h
 	$(CC) $(CFLAGS) -c -o$@ $<
 winshim.o : ../win/shim/winshim.c $(HACK_H)
 	$(CC) $(CFLAGS) -c -o$@ $<
diff --git a/sys/unix/hints/macOS.2020 b/sys/unix/hints/macOS.2020
index 44a1106bc..f9e3c8f58 100755
--- a/sys/unix/hints/macOS.2020
+++ b/sys/unix/hints/macOS.2020
@@ -298,7 +298,7 @@ ifdef WANT_LIBNH
 libnethack.a: $(HOBJ) $(LIBNHSYSOBJ) ../lib/lua/liblua.a
 	$(AR) rcs $@ $(HOBJ) $(LIBNHSYSOBJ) ../lib/lua/liblua.a
 	@echo "$@ built."
-libnethackmain.o : ../sys/lib/libnethackmain.c $(HACK_H)
+libnethackmain.o : ../sys/lib/libnethackmain.c $(HACK_H) ../include/date.h
 	$(CC) $(CFLAGS) -c -o$@ $<
 winshim.o : ../win/shim/winshim.c $(HACK_H)
 	$(CC) $(CFLAGS) -c -o$@ $<