diff --git a/packages/ponylang/0.39.0/build.sh b/packages/ponylang/0.39.0/build.sh
index bfedbde..8985661 100755
--- a/packages/ponylang/0.39.0/build.sh
+++ b/packages/ponylang/0.39.0/build.sh
@@ -7,10 +7,10 @@ curl -OL "https://github.com/ponylang/ponyc/archive/refs/tags/0.39.0.tar.gz"
 tar xfz 0.39.0.tar.gz
 
 # Build the vendored LLVM libraries that are included in the `lib/llvm/src`.
-make libs -j$(nproc)
+make libs build_flags="-j$(nproc)"
 # Configure the CMake build directory.
 make configure
 # Will build ponyc and put it in `build/release`.
 make build
 # Install ponyc into `$PREFIX`.
-make prefix="$PREFIX" install -j$(nproc)
+make prefix="$PREFIX" install