CI: download libev via conan, for windows builds to have it

windows builds so far was running with having libev available
and until this sync the fallback for python 3.12 was asyncio
eventloop, but now we fail and not fall back to asyncio.
so all unittest on windows are failing on any import from
cassandra.connection.

in this change we use conan to download libev, and using
it to compile the driver with libev

Ref: https://conan.io/center/recipes/libev

.github/workflows/build-push.yml

@@ -11,6 +11,7 @@ env:
  CIBW_BEFORE_BUILD_LINUX: "rm -rf ~/.pyxbld && yum install -y libffi-devel libev libev-devel openssl openssl-devel"
  CIBW_ENVIRONMENT: "CASS_DRIVER_BUILD_CONCURRENCY=2 CFLAGS='-g0 -O3'"
  CIBW_SKIP: cp35* cp36* *musllinux*
+ CIBW_BUILD_VERBOSITY: 3
 
 jobs:
   build_wheels:
@@ -65,6 +66,18 @@ jobs:
         run: |
           choco install openssl --version=3.3.1 -f -y
 
+      - name: Install Conan
+        if: runner.os == 'Windows'
+        uses: turtlebrowser/get-conan@main
+
+      - name: configure libev for Windows
+        if: runner.os == 'Windows'
+        run: |
+          conan profile detect
+          conan install conanfile.py
+          $env_vars = Get-Content .\build-release\conan\conandeps.env -Raw
+          echo "CIBW_ENVIRONMENT_WINDOWS=$env_vars" | Out-File -FilePath $Env:GITHUB_ENV -Encoding utf-8 -Append
+
       - name: Install OpenSSL for MacOS
         if: runner.os == 'MacOs'
         run: |

conanfile.py

@@ -0,0 +1,56 @@
+from pathlib import Path
+
+from conan import ConanFile
+from conan.tools.layout import basic_layout
+from conan.internal import check_duplicated_generator
+from conan.tools.files import save
+
+
+CONAN_COMMANDLINE_FILENAME = "conandeps.env"
+
+class CommandlineDeps:
+    def __init__(self, conanfile):
+        """
+        :param conanfile: ``< ConanFile object >`` The current recipe object. Always use ``self``.
+        """
+        self._conanfile = conanfile
+
+    def generate(self) -> None:
+        """
+        Collects all dependencies and components, then, generating a Makefile
+        """
+        check_duplicated_generator(self, self._conanfile)
+
+        host_req = self._conanfile.dependencies.host
+        build_req = self._conanfile.dependencies.build  # tool_requires
+        test_req = self._conanfile.dependencies.test
+
+        content_buffer = ""
+
+        # Filter the build_requires not activated for any requirement
+        dependencies = [tup for tup in list(host_req.items()) + list(build_req.items()) + list(test_req.items()) if not tup[0].build]
+
+        for require, dep in dependencies:
+            # Require is not used at the moment, but its information could be used, and will be used in Conan 2.0
+            if require.build:
+                continue
+            include_dir = Path(dep.package_folder) / 'include'
+            package_dir = Path(dep.package_folder) / 'lib'
+            content_buffer += f"CFLAGS='-I{include_dir}' LDFLAGS='-L{package_dir}'"
+
+        save(self._conanfile, CONAN_COMMANDLINE_FILENAME, content_buffer)
+        self._conanfile.output.info(f"Generated {CONAN_COMMANDLINE_FILENAME}")
+
+
+class python_driverConan(ConanFile):
+    win_bash = False
+
+    settings = "os", "compiler", "build_type", "arch"
+    requires = "libev/4.33"
+
+    def layout(self):
+        basic_layout(self)
+
+    def generate(self):
+        pc = CommandlineDeps(self)
+        pc.generate()