diff --git a/ci/test/00_setup_env_mac_host.sh b/ci/test/00_setup_env_mac_host.sh
index 14f1ea3ec..a710d983e 100644
--- a/ci/test/00_setup_env_mac_host.sh
+++ b/ci/test/00_setup_env_mac_host.sh
@@ -16,3 +16,6 @@ export OSX_SDK=""
 export CCACHE_SIZE=300M
 
 export RUN_SECURITY_TESTS="true"
+
+# Compiler for Mac native warns on C99 in dependencies.
+export NO_WERROR=1