Merge r1487528, r1563379, r1563381, r1565711 from trunk:

Merge r1487528, r1563379, r1563381, r1565711 from trunk:

* server/protocol.c (r_flush): Use int return type as per declaration
  of apr_vformatter(); no functional change.

Use %pm in order to save 8k of stack in 'ap_pcfg_strerror'

s/apr_pstrndup/apr_pstrmemdup/ when applicable

follow-up to r1096569:

remove unnecessary total_modules calculation

Submitted by: jorton, jailletc36, jailletc36, trawick
Reviewed/backported by: jim

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1569726 13f79535-47bb-0310-9956-ffa450edef68