Document in the man page that slapindex should be run as the same user
as slapd, and print a warning if it's run as root (since Debian defaults
to running slapd as openldap).

Not suitable for upstream in this form.  This patch needs to be reworked
to check the BerkeleyDB database ownership and only warn if running as
root with a database that's not owned by root.

Upstream ITS #5356 filed requesting better handling of this.  Current
upstream discussion leans towards putting the check into the database
backend and aborting if slapd is run as a different user than the database
owner, which is an even better fix.

--- a/doc/man/man8/slapindex.8
+++ b/doc/man/man8/slapindex.8
@@ -148,6 +148,10 @@
 should not be running (at least, not in read-write
 mode) when you do this to ensure consistency of the database.
 .LP
+slapindex ought to be run as the user specified for
+.BR slapd (8)
+to ensure correct database permissions.
+.LP
 This command provides ample opportunity for the user to obtain
 and drink their favorite beverage.
 .SH EXAMPLES
--- a/servers/slapd/slapindex.c
+++ b/servers/slapd/slapindex.c
@@ -34,6 +34,8 @@
 int
 slapindex( int argc, char **argv )
 {
+    if (geteuid() == 0)
+        fprintf( stderr, "\nWARNING!\nRunnig as root!\nThere's a fair chance slapd will fail to start.\nCheck file permissions!\n\n");
 	ID id;
 	int rc = EXIT_SUCCESS;
 	const char *progname = "slapindex";