locale.c white-space, comment, pod, C99 only

Previous commits, in trying to minimize the difference listings, have
left some indentations wrong, and comments out of order.  This commit
rectifies that.

It adds/clarifies many comments, rewords some pod, and moves some
declarations closer to first use (now that we are using C99).

There should be no change in the compiled code.

Author: khwilliamson