diff --git a/sh/pre b/sh/pre
new file mode 100755
index 0000000..85da5d5
--- /dev/null
+++ b/sh/pre
@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+if [ -n "${ZSH_VERSION:-}" ]; then
+    $CC -dM -E - $=CFLAGS $=LDFLAGS < /dev/null
+else
+    $CC -dM -E - $CFLAGS $LDFLAGS < /dev/null
+fi