diff --git a/.circleci/config.yml b/.circleci/config.yml
index 299913225..9e32298cc 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -261,7 +261,8 @@ jobs:
                 gcc-c++-5.5.0 \
                 python-2.7.15 \
                 libffi-3.2.1 \
-                libyaml-0.1.6 </dev/null
+                libyaml-0.1.6 \
+                libmpc-1.0.3 </dev/null
 
             slackpkg upgrade \
                 openssl-1.0 </dev/null