diff --git a/src/Make_ming.mak b/src/Make_ming.mak
index 8e523a2..9402ccc 100644
--- a/src/Make_ming.mak
+++ b/src/Make_ming.mak
@@ -301,7 +301,14 @@
 endif
 endif
 
-RUBYINC =-I $(RUBY)/lib/ruby/$(RUBY_VER_LONG)/$(RUBY_PLATFORM) -I $(RUBY)/include/ruby-$(RUBY_VER_LONG) -I $(RUBY)/include/ruby-$(RUBY_VER_LONG)/$(RUBY_PLATFORM)
+ifeq (19, $(word 1,$(sort 19 $(RUBY_VER))))
+RUBY_19_OR_LATER = 1
+endif
+
+RUBYINC = -I $(RUBY)/lib/ruby/$(RUBY_VER_LONG)/$(RUBY_PLATFORM)
+ifdef RUBY_19_OR_LATER
+RUBYINC += -I $(RUBY)/include/ruby-$(RUBY_VER_LONG) -I $(RUBY)/include/ruby-$(RUBY_VER_LONG)/$(RUBY_PLATFORM)
+endif
 ifeq (no, $(DYNAMIC_RUBY))
 RUBYLIB = -L$(RUBY)/lib -l$(RUBY_INSTALL_NAME)
 endif