Revision 395187

Merge r384731, r386790, r386821 from trunk.

    *  Unsure why win32 never noticed this, but the value returned is a const
       char*

    *  Escape from casting purgatory, which the Solaris cc compiler
       will not treat as lvalues.

    * Eliminate last win32-isms, SetLastError becomes apr's set_os_error
      operation.  It unfolds the error code on win32, so we have to pre-fold
      it.  On unix there is no folding.