Renumber GUC flags for a bit more sanity.

Push the units fields over to the left so that all the single-bit
flags can be together.  I considered rearranging the single-bit
flags to try to group flags with similar purposes, but eventually
decided that that involved too many judgment calls.

Discussion: https://postgr.es/m/17385-9ee529fb091f0ce5@postgresql.org

Author: tglsfdc

src/include/utils/guc.h

@@ -202,44 +202,39 @@ typedef enum
 #define GUC_QUALIFIER_SEPARATOR '.'
 
 /*
- * bit values in "flags" of a GUC variable
+ * Bit values in "flags" of a GUC variable.  Note that these don't appear
+ * on disk, so we can reassign their values freely.
  */
-#define GUC_LIST_INPUT			0x0001	/* input can be list format */
-#define GUC_LIST_QUOTE			0x0002	/* double-quote list elements */
-#define GUC_NO_SHOW_ALL			0x0004	/* exclude from SHOW ALL */
-#define GUC_NO_RESET		  0x400000	/* disallow RESET and SAVE */
-#define GUC_NO_RESET_ALL		0x0008	/* exclude from RESET ALL */
-#define GUC_REPORT				0x0010	/* auto-report changes to client */
-#define GUC_NOT_IN_SAMPLE		0x0020	/* not in postgresql.conf.sample */
-#define GUC_DISALLOW_IN_FILE	0x0040	/* can't set in postgresql.conf */
-#define GUC_CUSTOM_PLACEHOLDER	0x0080	/* placeholder for custom variable */
-#define GUC_SUPERUSER_ONLY		0x0100	/* show only to superusers */
-#define GUC_IS_NAME				0x0200	/* limit string to NAMEDATALEN-1 */
-#define GUC_NOT_WHILE_SEC_REST	0x0400	/* can't set if security restricted */
-#define GUC_DISALLOW_IN_AUTO_FILE 0x0800	/* can't set in
-											 * PG_AUTOCONF_FILENAME */
-
-#define GUC_UNIT_KB				0x1000	/* value is in kilobytes */
-#define GUC_UNIT_BLOCKS			0x2000	/* value is in blocks */
-#define GUC_UNIT_XBLOCKS		0x3000	/* value is in xlog blocks */
-#define GUC_UNIT_MB				0x4000	/* value is in megabytes */
-#define GUC_UNIT_BYTE			0x5000	/* value is in bytes */
-#define GUC_UNIT_MEMORY			0xF000	/* mask for size-related units */
-
-#define GUC_UNIT_MS			   0x10000	/* value is in milliseconds */
-#define GUC_UNIT_S			   0x20000	/* value is in seconds */
-#define GUC_UNIT_MIN		   0x30000	/* value is in minutes */
-#define GUC_UNIT_TIME		   0xF0000	/* mask for time-related units */
-
-#define GUC_EXPLAIN			  0x100000	/* include in explain */
-
-/*
- * GUC_RUNTIME_COMPUTED is intended for runtime-computed GUCs that are only
- * available via 'postgres -C' if the server is not running.
- */
-#define GUC_RUNTIME_COMPUTED  0x200000
-
-#define GUC_UNIT				(GUC_UNIT_MEMORY | GUC_UNIT_TIME)
+#define GUC_LIST_INPUT		   0x000001 /* input can be list format */
+#define GUC_LIST_QUOTE		   0x000002 /* double-quote list elements */
+#define GUC_NO_SHOW_ALL		   0x000004 /* exclude from SHOW ALL */
+#define GUC_NO_RESET		   0x000008 /* disallow RESET and SAVE */
+#define GUC_NO_RESET_ALL	   0x000010 /* exclude from RESET ALL */
+#define GUC_EXPLAIN			   0x000020 /* include in EXPLAIN */
+#define GUC_REPORT			   0x000040 /* auto-report changes to client */
+#define GUC_NOT_IN_SAMPLE	   0x000080 /* not in postgresql.conf.sample */
+#define GUC_DISALLOW_IN_FILE   0x000100 /* can't set in postgresql.conf */
+#define GUC_CUSTOM_PLACEHOLDER 0x000200 /* placeholder for custom variable */
+#define GUC_SUPERUSER_ONLY	   0x000400 /* show only to superusers */
+#define GUC_IS_NAME			   0x000800 /* limit string to NAMEDATALEN-1 */
+#define GUC_NOT_WHILE_SEC_REST 0x001000 /* can't set if security restricted */
+#define GUC_DISALLOW_IN_AUTO_FILE \
+							   0x002000 /* can't set in PG_AUTOCONF_FILENAME */
+#define GUC_RUNTIME_COMPUTED   0x004000 /* delay processing in 'postgres -C' */
+
+#define GUC_UNIT_KB			 0x01000000 /* value is in kilobytes */
+#define GUC_UNIT_BLOCKS		 0x02000000 /* value is in blocks */
+#define GUC_UNIT_XBLOCKS	 0x03000000 /* value is in xlog blocks */
+#define GUC_UNIT_MB			 0x04000000 /* value is in megabytes */
+#define GUC_UNIT_BYTE		 0x05000000 /* value is in bytes */
+#define GUC_UNIT_MEMORY		 0x0F000000 /* mask for size-related units */
+
+#define GUC_UNIT_MS			 0x10000000 /* value is in milliseconds */
+#define GUC_UNIT_S			 0x20000000 /* value is in seconds */
+#define GUC_UNIT_MIN		 0x30000000 /* value is in minutes */
+#define GUC_UNIT_TIME		 0x70000000 /* mask for time-related units */
+
+#define GUC_UNIT			 (GUC_UNIT_MEMORY | GUC_UNIT_TIME)
 
 
 /* GUC vars that are actually defined in guc_tables.c, rather than elsewhere */