diff --git a/libcxx/utils/ci/run-buildbot b/libcxx/utils/ci/run-buildbot
--- a/libcxx/utils/ci/run-buildbot
+++ b/libcxx/utils/ci/run-buildbot
@@ -457,7 +457,7 @@
           -DCMAKE_BUILD_TYPE=RelWithDebInfo \
           -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" \
           -DLLVM_ENABLE_PROJECTS="clang" \
-          -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi" \
+          -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind" \
           -DLLVM_RUNTIME_TARGETS="$(c++ --print-target-triple)" \
           -DLLVM_TARGETS_TO_BUILD="host" \
           -DRUNTIMES_BUILD_ALLOW_DARWIN=ON \