Enable --with-libidn2 in GitLab CI checks

.gitlab-ci.yml

@@ -88,7 +88,7 @@ stages:
     - test -w "${CCACHE_DIR}" && export PATH="/usr/lib/ccache:${PATH}"
     - ./autogen.sh
   script:
-    - ./configure --enable-developer --with-libtool --disable-static --with-atf=/usr/local
+    - ./configure --enable-developer --with-libtool --disable-static --with-atf=/usr/local --with-libidn2
     - make -j${PARALLEL_JOBS_BUILD:-1} -k all V=1
   artifacts:
     expire_in: '1 hour'