Removed deprecated libcurl backend (#4083)

Author: JohanMabille

.github/workflows/static_build.yml

@@ -45,6 +45,17 @@ jobs:
         run: |
           cd micromamba-feedstock/
           sed -i '' '/conda_forge_output_validation/d' conda-forge.yml
+      - name: Replaces python 3.9 with 3.13
+        if: ${{ matrix.platform == 'linux' }}
+        run: |
+          cd micromamba-feedstock/recipe/
+          sed -i 's|    - micromamba{{ bin_ext }} create -n test --override-channels -c conda-forge --yes python=3\.9|    - micromamba{{ bin_ext }} create -n test --override-channels -c conda-forge --yes python=3.13|' meta.yaml
+      - name: Uses libcurl 8.14
+        if: ${{ matrix.platform == 'linux' }}
+        run: |
+          cd micromamba-feedstock/recipe/
+          sed -i 's|    - libcurl >=8\.4\.0[[:space:]]*# \[unix\]|    - libcurl >=8.4,<8.15    #[unix]|' meta.yaml
+          sed -i 's|    - libcurl-static >=8\.4\.0[[:space:]]*# \[unix\]|    - libcurl-static >=8.4,<8.15    #[unix]|' meta.yaml
       - name: Checkout mamba branch
         uses: actions/checkout@v4
         with:

libmamba/src/core/singletons.cpp

@@ -88,18 +88,10 @@ namespace mamba
             CURLsslset sslset_res;
             const curl_ssl_backend** available_backends;
 
-            if (util::on_linux)
+            if (util::on_linux || util::on_mac)
             {
                 sslset_res = curl_global_sslset(CURLSSLBACKEND_OPENSSL, nullptr, &available_backends);
             }
-            else if (util::on_mac)
-            {
-                sslset_res = curl_global_sslset(
-                    CURLSSLBACKEND_SECURETRANSPORT,
-                    nullptr,
-                    &available_backends
-                );
-            }
             else if (util::on_win)
             {
                 sslset_res = curl_global_sslset(CURLSSLBACKEND_SCHANNEL, nullptr, &available_backends);

libmamba/src/download/curl.cpp

@@ -281,13 +281,6 @@ namespace mamba::download
             {
                 log = std::make_pair(std::string_view("Using OpenSSL backend"), CurlLogLevel::kInfo);
             }
-            else if (info->backend == CURLSSLBACKEND_SECURETRANSPORT)
-            {
-                log = std::make_pair(
-                    std::string_view("Using macOS SecureTransport backend"),
-                    CurlLogLevel::kInfo
-                );
-            }
             else if (info->backend == CURLSSLBACKEND_SCHANNEL)
             {
                 log = std::make_pair(