python-cryptography: patch pyo3 for cygwin support

and remove the MSYSTEM hack since maturin now works without it.

python-cryptography/0001-Explicitely-link-with-libpython-on-Cygwin.patch

@@ -0,0 +1,28 @@
+From be3b2f227a6cc60e27f2b74e9f301bcc136183e6 Mon Sep 17 00:00:00 2001
+From: Christoph Reiter <reiter.christoph@gmail.com>
+Date: Wed, 29 Oct 2025 08:26:50 +0100
+Subject: [PATCH 1/2] Explicitely link with libpython on Cygwin
+
+Like with Windows Python, under Cygwin we need to explicitely
+link with libpython.
+
+Thix fixes the build under Cygwin.
+---
+ pyo3-build-config/src/impl_.rs | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/pyo3-build-config/src/impl_.rs b/pyo3-build-config/src/impl_.rs
+index cca9393d..b977ac79 100644
+--- a/pyo3-build-config/src/impl_.rs
++++ b/pyo3-build-config/src/impl_.rs
+@@ -890,6 +890,7 @@ pub fn is_linking_libpython_for_target(target: &Triple) -> bool {
+         || target.operating_system == OperatingSystem::Aix
+         || target.environment == Environment::Android
+         || target.environment == Environment::Androideabi
++        || target.operating_system == OperatingSystem::Cygwin
+         || !is_extension_module()
+ }
+ 
+-- 
+2.51.2
+