[ruby-core:44371] dln_load and rb_w32_check_imported cause segfault in Ruby 1.9.3 for some extension

Hello,

NOTE: Reporting this here since bugs.ruby-lang.org seems to be down.

Recently a user reported to RubyInstaller project issues when loading
a Ruby 1.9.2 compiled extension under Ruby 1.9.3:

https://groups.google.com/d/msg/rubyinstaller/aSezE2LwfQs/TDZvPG3X5mUJ

Which I was able to study a bit better:
https://groups.google.com/d/msg/rubyinstaller/aSezE2LwfQs/UGKlButpNfMJ

To add more, my last comment was:

"Is worth to mention that this do not fail against 1.9.2 (either
building or running) but dln_load mechanism on Ruby 1.9.2 differs from
Ruby 1.9.3 and highly unlikely is going to change."

I'm not convinced by my last comment and I do believe this is a bug.
db2cli.dll links to MSVCR80 and even so, it loads properly under
1.9.2.

Looking closely to what rb_w32_check_imported does, it is supposed to
verify that the extension being loaded it is indeed using the right
ruby dll.

But is failing to obtain Name from pii (PIMAGE_IMPORT_BY_NAME struct)

I can't find any reference to dbghelp (which provides
ImageDirectoryEntryToData) being included or linked in
msvcrt-libruby191.dll

For sure I'm missing something, specially why is failing to obtain
this extension information when works for others.

Thank you.
-- 
Luis Lavena
AREA 17
-
Perfection in design is achieved not when there is nothing more to add,
but rather when there is nothing more to take away.
Antoine de Saint-Exup駻y