Merge r384731, r386790, and r386821 from trunk:

    * mod_isapi: Trivial compiler emit fixes for const'ness - noticed on OS/X
      Correct lvalue assignments (lvalue casts not allowed) - noticed on Sol.
      Resolve use of SetLastError with apr_set_os_error() and axe MAKEFILE
      for a literal value.  Permits mod_isapi to load and run on Unix.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@390723 13f79535-47bb-0310-9956-ffa450edef68