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

helpers.c

@@ -0,0 +1,28 @@
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "helpers.h"
+
+#ifdef EXPLAIN
+int explain = 0;
+#endif
+
+#if defined(ERR) || defined(EXPLAIN)
+void
+l(const char *fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  vfprintf(stderr, fmt, ap);
+  va_end(ap);
+
+  if (fmt[0] && fmt[strlen(fmt) - 1] == ':') {
+    fputc(' ', stderr);
+    perror(NULL);
+  } else {
+    fputc('\n', stderr);
+  }
+}
+#endif