Merge r1551611, r1783765, r1788996, r1788998, r1789000, r1795651 from trunk:
Log a warning when the LDAP authn provider is configured but an AuthLDAPURL isn't -- IOW, avoid silently skipping a misconfigured [or buggy?] LDAP provider.
Follow up to r1772919: update APLOGNO().
Save a few cycles. 'apr_pstrcatv' can compute the length of the new string for us.
Group bit field values in order to save some memory.
Add an explicit NULL to initialise a field in an authn_provider structure, as done in all other places. PR 60636 Submitted by: covener, ylavic, jailletc36, jailletc36, jailletc36, jailletc36 Reviewed by: jailletc36, jim, ylavic