diff --git a/build-aux/ci/summarize-coverage b/build-aux/ci/summarize-coverage
index 0cfd4bec..8c6d30cd 100755
--- a/build-aux/ci/summarize-coverage
+++ b/build-aux/ci/summarize-coverage
@@ -15,10 +15,11 @@ set -x
 # Merge all of the gcov output into one overview file using lcov,
 # then prune data for the tests themselves, and for system libraries.
 
-lcov --gcov-tool "$GCOV" --rc lcov_branch_coverage=1 \
-     --directory . --output-file "$unpruned" \
-     --capture
+lcov --gcov-tool "$GCOV" --ignore-errors unused \
+     --rc branch_coverage=1 --directory . \
+     --output-file "$unpruned" --capture
 
-lcov --gcov-tool "$GCOV" --rc lcov_branch_coverage=1 \
-     --directory . --output-file "$1" \
+lcov --gcov-tool "$GCOV" --ignore-errors unused \
+     --rc branch_coverage=1 --directory . \
+     --output-file "$1" \
      --remove "$unpruned" '/usr/*' '*test*'