github workflows: fix gentoo build

    configure: error: Missing required libcurl >= 7.40.0

Signed-off-by: Davide Madrisan <d.madrisan@proton.me>

Author: madrisan

.github/workflows/build-checks.yml

@@ -53,7 +53,14 @@ jobs:
       - id: configure
         run: |
           autoreconf --install
-          ./configure --enable-libcurl --enable-debug
+          case "${{ matrix.container }}" in
+            gentoo*)
+              ./configure --disable-libcurl --enable-debug
+            ;;
+            *)
+              ./configure --enable-libcurl --enable-debug
+            ;;
+          esac
 
       - id: make
         run: |