Disable DLL detach handlers on cygwin

Disable DLL detach handlers on cygwin

This patch is from cygwin, and was originally added in:

https://cygwin.com/cgit/cygwin-packages/openssl/commit/?id=da80cc438622f6b1801fb3fbb06818c3ee070495

In cygwin, it's not safe to call into libc from
DLL_THREAD/PROCESS_DETACH, and it results in crashes.

CLA: trivial

Co-authored-By: Achim Gratz <Achim.Gratz@Stromeko.DE>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Tomas Mraz <tomas@openssl.foundation>
MergeDate: Thu Mar 19 10:04:53 2026
(Merged from https://github.com/openssl/openssl/pull/29321)