we have to patch the code so that it takes the RUBY_DESCRIPTION into
consideration, to avoid loading Ruby-Enterprise (REE18) objects in MRI
and vice-versa; we're a bit “greedier” since we will rebuild objects
even when just switching versions, but it'll be better this way than
being too conservatives.

Index: ruby-inline-3.8.4/lib/inline.rb
===================================================================
--- ruby-inline-3.8.4.orig/lib/inline.rb
+++ ruby-inline-3.8.4/lib/inline.rb
@@ -360,13 +360,18 @@ module Inline
       ext.join "\n"
     end
 
+    def implementation_checksum
+      @implementation_checksum ||=
+        (Digest::MD5.new << RUBY_DESCRIPTION).to_s[0,4]
+    end
+
     def module_name
       unless defined? @module_name then
         module_name = @mod.name.gsub('::','__')
         md5 = Digest::MD5.new
         @pre.each { |m| md5 << m.to_s }
         @sig.keys.sort_by { |x| x.to_s }.each { |m| md5 << m.to_s }
-        @module_name = "Inline_#{module_name}_#{md5}"
+        @module_name = "Inline_#{module_name}_#{md5}_#{implementation_checksum}"
       end
       @module_name
     end
Index: ruby-inline-3.8.4/test/test_inline.rb
===================================================================
--- ruby-inline-3.8.4.orig/test/test_inline.rb
+++ ruby-inline-3.8.4/test/test_inline.rb
@@ -404,6 +404,7 @@ static VALUE method_name_equals(VALUE se
   end
 
   def util_module_name(*signatures)
+    implementation = (Digest::MD5.new << RUBY_DESCRIPTION).to_s[0,4]
     md5 = Digest::MD5.new
 
     signatures.each do |signature|
@@ -411,6 +412,6 @@ static VALUE method_name_equals(VALUE se
       md5 << signature.to_s
     end
 
-    assert_equal("Inline_TestInline__TestC_#{md5}", @builder.module_name)
+    assert_equal("Inline_TestInline__TestC_#{md5}_#{implementation}", @builder.module_name)
   end
 
@@ -757,6 +758,7 @@ puts(s); return rb_str_new2(s)}"
     @builder.c "VALUE my_method() { return Qnil; }"
 
     windoze = "\n  __declspec(dllexport)" if Inline::WINDOZE
+    implementation = (Digest::MD5.new << RUBY_DESCRIPTION).to_s[0,4]
 
     expected = <<-EXT
 #include "ruby.h"
@@ -773,7 +775,7 @@ static VALUE my_method(VALUE self) {
 #ifdef __cplusplus
 extern \"C\" {
 #endif#{windoze}
-  void Init_Inline_TestInline__TestC_3ab8c09639e499394bb1f0a0194a839f() {
+  void Init_Inline_TestInline__TestC_3ab8c09639e499394bb1f0a0194a839f_#{implementation}() {
     VALUE c = rb_cObject;
     c = rb_const_get(c, rb_intern("TestInline"));
     c = rb_const_get(c, rb_intern("TestC"));