Move PG_AUTOCONF_FILENAME definition

Since this is not something that a user should change,
pg_config_manual.h was an inappropriate place for it.

In initdb.c, remove the use of the macro, because utils/guc.h can't be
included by non-backend code.  But we hardcode all the other
configuration file names there, so this isn't a disaster.

src/bin/initdb/initdb.c

@@ -1366,7 +1366,7 @@ setup_config(void)
 	autoconflines[1] = pg_strdup("# It will be overwritten by the ALTER SYSTEM command.\n");
 	autoconflines[2] = NULL;
 
-	sprintf(path, "%s/%s", pg_data, PG_AUTOCONF_FILENAME);
+	sprintf(path, "%s/postgresql.auto.conf", pg_data);
 
 	writefile(path, autoconflines);
 	if (chmod(path, S_IRUSR | S_IWUSR) != 0)

src/include/pg_config_manual.h

@@ -305,10 +305,3 @@
  */
 /* #define HEAPDEBUGALL */
 /* #define ACLDEBUG */
-
-/*
- * Automatic configuration file name for ALTER SYSTEM.
- * This file will be used to store values of configuration parameters
- * set by ALTER SYSTEM command.
- */
-#define PG_AUTOCONF_FILENAME		"postgresql.auto.conf"

src/include/utils/guc.h

@@ -26,6 +26,13 @@
 #define MAX_KILOBYTES	(INT_MAX / 1024)
 #endif
 
+/*
+ * Automatic configuration file name for ALTER SYSTEM.
+ * This file will be used to store values of configuration parameters
+ * set by ALTER SYSTEM command.
+ */
+#define PG_AUTOCONF_FILENAME		"postgresql.auto.conf"
+
 /*
  * Certain options can only be set at certain times. The rules are
  * like this: