diff --git a/build/build.sh b/build/build.sh
index 02a4b14..0e2f2f3 100755
--- a/build/build.sh
+++ b/build/build.sh
@@ -50,6 +50,7 @@ p1061-trunk)
     BRANCH=ricejasonf/p1061
     URL=https://github.com/ricejasonf/llvm-project.git
     VERSION=p1061-trunk-$(date +%Y%m%d)
+    LLVM_ENABLE_RUNTIMES+=";libunwind"
     ;;
 embed-trunk)
     BRANCH=feature/embed