diff --git a/common.mk b/common.mk
index 0242699118..7bf6d28b53 100644
--- a/common.mk
+++ b/common.mk
@@ -861,7 +861,10 @@ clean-platform distclean-platform realclean-platform:
 
 RUBYSPEC_CAPIEXT = spec/ruby/optional/capi/ext
 RUBYSPEC_CAPIEXT_SRCDIR = $(srcdir)/$(RUBYSPEC_CAPIEXT)
-RUBYSPEC_CAPIEXT_DEPS = $(RUBYSPEC_CAPIEXT_SRCDIR)/rubyspec.h $(RUBY_H_INCLUDES) $(LIBRUBY) build-ext
+RUBYSPEC_CAPIEXT_DEPS = $(RUBYSPEC_CAPIEXT_SRCDIR)/rubyspec.h $(RUBY_H_INCLUDES) $(LIBRUBY)
+
+rubyspec-capiext: build-ext $(DOT_WAIT)
+# make-dependent rules should be included after this and built after build-ext.
 
 clean-spec: PHONY
 	-$(Q) $(RM) $(RUBYSPEC_CAPIEXT)/*.$(OBJEXT) $(RUBYSPEC_CAPIEXT)/*.$(DLEXT)
diff --git a/defs/gmake.mk b/defs/gmake.mk
index 666e057c9d..6e696c4631 100644
--- a/defs/gmake.mk
+++ b/defs/gmake.mk
@@ -506,7 +506,8 @@ update-deps:
 
 # order-only-prerequisites doesn't work for $(RUBYSPEC_CAPIEXT)
 # because the same named directory exists in the source tree.
-$(RUBYSPEC_CAPIEXT)/%.$(DLEXT): $(srcdir)/$(RUBYSPEC_CAPIEXT)/%.c $(RUBYSPEC_CAPIEXT_DEPS)
+$(RUBYSPEC_CAPIEXT)/%.$(DLEXT): $(srcdir)/$(RUBYSPEC_CAPIEXT)/%.c $(RUBYSPEC_CAPIEXT_DEPS) \
+	| build-ext
 	$(ECHO) building $@
 	$(Q) $(MAKEDIRS) $(@D)
 	$(Q) $(DLDSHARED) -L. $(XDLDFLAGS) $(XLDFLAGS) $(LDFLAGS) $(INCFLAGS) $(CPPFLAGS) $(OUTFLAG)$@ $< $(LIBRUBYARG)