[COMMITTED] Fix GCC6 build errors due to unused statics

[Wilco Dijkstra]

> Joseph Myers wrote:
> On Fri, 18 Sep 2015, Wilco Dijkstra wrote:
> 
> > 	* timezone/private.h (time_t_min): Likewise.  (time_t_max):
> > 	Likewise.
> 
> The timezone/ code is imported verbatim from upstream tzcode releases and
> should not be changed locally.  Please revert this change and work with
> Paul on getting a fix into upstream tzcode.  When there's a new tzcode
> release, you can then import it into glibc.  (Some Makefile changes will
> be needed as part of the import of new code; see
> <https://sourceware.org/ml/libc-alpha/2015-05/msg00553.html>.  Do not try
> to combine this with importing a new version of tzdata.)

Would it be OK to change the Makefile instead to ignore this error?

Wilco