perf: optimize CI build performance

- Add -C flag to configure for caching
- Use ccache for faster recompilation

ci-build.sh

@@ -183,11 +183,11 @@ esac
 case "$ARCH" in
     linux*)
          echo
-         echo "--> Building with ./configure ${tests[0]} --enable-valgrind $*"
+         echo "--> Building with ./configure -C ${tests[0]} --enable-valgrind $*"
          echo
 
          # shellcheck disable=SC2086
-        ./configure ${tests[0]} --enable-valgrind $*
+        ./configure -C ${tests[0]} --enable-valgrind $*
 
         $MAKE CC="${CC}"
         if grep '^ID=' /etc/os-release | grep -q -e debian; then
@@ -209,13 +209,13 @@ build_and_test() {
 
     {
         echo "=== Build $idx started at $(date) ==="
-        echo "--> Building in $build_dir with ./configure $features $extra_args"
+        echo "--> Building in $build_dir with ./configure -C $features $extra_args"
 
         mkdir -p "$build_dir"
         cd "$build_dir"
 
         # shellcheck disable=SC2086
-        ../configure $features $extra_args
+        ../configure -C $features $extra_args
 
         $MAKE CC="${CC}"
         $MAKE check-functional-parallel