diff --git a/third_party/nix/pkgs/bison/yacc.in b/third_party/nix/pkgs/bison/yacc.in
new file mode 100644
index 0000000..b6ff366
--- /dev/null
+++ b/third_party/nix/pkgs/bison/yacc.in
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# The exec-prefix is used by YACC to find Bison at runtime.
+# Since we don't exactly know that, we have to depend on an
+# environment variable we set in Bazel.
+exec "$BISON" -y "$@"
\ No newline at end of file