+/* First define a measure of the amount of data we have. */
+
+/* A system configuration file may set this to request a certain extra
+ amount of storage. This is a lot more update-robust that defining
+ BASE_PURESIZE or even PURESIZE directly. */
+#ifndef SYSTEM_PURESIZE_EXTRA
+#define SYSTEM_PURESIZE_EXTRA 0
+#endif
+
+#ifndef SITELOAD_PURESIZE_EXTRA
+#define SITELOAD_PURESIZE_EXTRA 0
+#endif
+
+#ifndef BASE_PURESIZE
+#define BASE_PURESIZE (1100000 + SYSTEM_PURESIZE_EXTRA + SITELOAD_PURESIZE_EXTRA)
+#endif
+
+/* Increase BASE_PURESIZE by a ratio depending on the machine's word size. */
+#ifndef PURESIZE_RATIO
+#if BITS_PER_EMACS_INT > 32
+#define PURESIZE_RATIO 9/5 /* Don't surround with `()'. */