Implement a new caching system to make repeated runs much much faster.

helpers.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#if defined(ERR) || defined(EXPLAIN)
+void l(const char *fmt, ...);
+#endif
+
+#ifdef ERR
+#define L(...) l(__VA_ARGS__)
+#else
+#define L(...)
+#endif
+
+#ifdef EXPLAIN
+extern int explain;
+#define E(...) if (explain) {    \
+                 l(__VA_ARGS__); \
+               } else
+#else
+#define E(...)
+#endif