diff --git a/common.mk b/common.mk
index 8999201cc1..e086eeb0f3 100644
--- a/common.mk
+++ b/common.mk
@@ -146,7 +146,7 @@ miniruby$(EXEEXT): config.status $(NORMALMAINOBJ) $(MINIOBJS) $(COMMONOBJS) $(DM
 GORUBY = go$(RUBY_INSTALL_NAME)
 golf: $(LIBRUBY) $(GOLFOBJS) PHONY
 	$(MAKE) $(MFLAGS) MAINOBJ="$(GOLFOBJS)" PROGRAM=$(GORUBY)$(EXEEXT) program
-capi: Doxyfile PHONY
+capi: Doxyfile PHONY $(PREP)
 	@$(MAKEDIRS) doc/capi
 	@$(DOXYGEN)
 
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index 50d722b58a..416921403e 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -237,6 +237,7 @@ RUNRUBY = $(RUNRUBY) "$(srcdir)/tool/runruby.rb" --extout="$(EXTOUT)" $(RUNRUBYO
 !ifndef RUBY
 RUBY = ruby
 !endif
+MAKEDIRS = @$(MINIRUBY) -run -e mkdir -- -p
 
 !if !defined(STACK)
 !if "$(ARCH)" == "x64" || "$(ARCH)" == "ia64"