[tz] zdump broken with -DUSE_LTZ=0

[Joseph Myers]

I tried updating the copy of tzcode in glibc.  I found that as of the 
latest release and current git, zdump doesn't build with -DUSE_LTZ=0, 
because that configuration disables the inclusion of private.h, which 
defines the INITIALIZE macro which zdump now uses unconditionally.  
(There's also a -Wundef issue with the "#if !HAVE_POSIX_DECLS", as that's 
also only defined in private.h, but that's easy to work around.)

-- 
Joseph S. Myers
joseph at codesourcery.com