Merge r1866894 from trunk:

* modules/mappers/mod_rewrite.c: Enhance trace-level logging to log
  line numbers accurately for C99 compilers, and remove odd/awkward
  double-parentheses using the rewritelog() macro.  For non-C99
  compilers do_rewritelog() will now be defined - but as a noop - if
  REWRITELOG_DISABLED is defined at compile time.

No functional change at runtime apart from the line numbers being
fixed.

NOTE: minimises whitespace differences between 2.4.x and trunk
      to ease merging future changes