diff --git a/ci/config.mk.sed b/ci/config.mk.sed
index 51e7ec9..f672edd 100644
--- a/ci/config.mk.sed
+++ b/ci/config.mk.sed
@@ -1,3 +1,3 @@
 /^CFLAGS[[:blank:]]*=/s/$/ -Wall -Wextra -Wshadow -Werror/
-/^PERL_CFLAGS_EXTRA[[:blank:]]*=/s/$/ -Wno-error=unused-function/
+/^PERL_CFLAGS_EXTRA[[:blank:]]*=/s/$/ -Wno-error=unused-function -Wno-shadow/
 /^RUBY_CFLAGS_EXTRA[[:blank:]]*=/s/$/ -Wno-error=unused-parameter/