--- ruby-2.6.5/Makefile.in.orig	2019-10-01 20:01:01.000000000 +0900
+++ ruby-2.6.5/Makefile.in	2019-11-08 10:06:55.159925000 +0900
@@ -289,1 +289,1 @@
 		@$(RMALL) conftest$(EXEEXT) conftest.c conftest.dSYM

 $(LIBRUBY_SO):
-		@-[ -n "$(EXTSTATIC)" ] || $(PRE_LIBRUBY_UPDATE)
+		@$(RM) $@
+		@-[ -z "$(EXTSTATIC)" ] || $(PRE_LIBRUBY_UPDATE)
 		$(ECHO) linking shared-library $@
 		$(Q) $(LDSHARED) $(DLDFLAGS) $(OBJS) $(DLDOBJS) $(SOLIBS) $(EXTSOLIBS) $(OUTFLAG)$@
 		-$(Q) $(OBJCOPY) -w -L '$(SYMBOL_PREFIX)Init_*' -L '$(SYMBOL_PREFIX)ruby_static_id_*' \