diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 301bf52204..1a17340c00 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -1003,7 +1003,7 @@ RUBY_SYMBOL_EXPORT_END
 }  /* extern "C" { */
 #endif
 
-#if defined(__has_attribute) && defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P)
+#if defined(__has_attribute) && defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P) && !defined(_WIN32)
 #if __has_attribute(transparent_union) && __has_attribute(unused) && __has_attribute(weakref) && __has_attribute(nonnull)
 __attribute__((__unused__,__weakref__("rb_define_method_id"),__nonnull__(3)))static void rb_define_method_idm3(VALUE,ID,VALUE(*)(ANYARGS),int);
 __attribute__((__unused__,__weakref__("rb_define_method_id"),__nonnull__(3)))static void rb_define_method_idm2(VALUE,ID,VALUE(*)(VALUE,VALUE),int);
@@ -1171,19 +1171,4 @@ __attribute__((__unused__,__weakref__("rb_define_singleton_method"),__nonnull__(
 #endif
 #endif
 
-#ifdef _WIN32
-#ifdef rb_define_method_id
-#undef rb_define_method_id
-#endif
-#ifdef rb_define_private_function
-#undef rb_define_private_function
-#endif
-#ifdef rb_define_protected_function
-#undef rb_define_protected_function
-#endif
-#ifdef rb_define_singleton_function
-#undef rb_define_singleton_function
-#endif
-#endif
-
 #endif /* RUBY_INTERN_H */
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 8764443e3a..652dcc30de 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -2689,7 +2689,7 @@ RUBY_SYMBOL_EXPORT_END
 }  /* extern "C" { */
 #endif
 
-#if defined(__has_attribute) && defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P)
+#if defined(__has_attribute) && defined(HAVE_BUILTIN___BUILTIN_CHOOSE_EXPR_CONSTANT_P) && !defined(_WIN32)
 #if __has_attribute(transparent_union) && __has_attribute(unused) && __has_attribute(weakref) && __has_attribute(nonnull)
 __attribute__((__unused__,__weakref__("rb_define_method"),__nonnull__(2,3)))static void rb_define_methodm3(VALUE,const char*,VALUE(*)(ANYARGS),int);
 __attribute__((__unused__,__weakref__("rb_define_method"),__nonnull__(2,3)))static void rb_define_methodm2(VALUE,const char*,VALUE(*)(VALUE,VALUE),int);
@@ -2818,16 +2818,4 @@ __attribute__((__unused__,__weakref__("rb_define_global_function"),__nonnull__(1
 #endif
 #endif
 
-#ifdef _WIN32
-#ifdef rb_define_method
-#undef rb_define_method
-#endif
-#ifdef rb_define_module_function
-#undef rb_define_module_function
-#endif
-#ifdef rb_define_global_function
-#undef rb_define_global_function
-#endif
-#endif
-
 #endif /* RUBY_RUBY_H */