[tz] [PATCH 0/1] Allow 'backzone' to be incorporated in 'right' data

[Paul Eggert]

On 09/29/2015 07:06 AM, Ian Abbott wrote:
> I think that would mean replacing the 'REDO' macro with separate 
> macros to control whether the main set of data is 'posix' or 'right', 
> whether the second (opposite) set of data is to be made available, and 
> whether the 'backzone' data is to be incorporated

Yes, something like that.  The basic idea is that the makefile should 
grow linearly with the number of installation options, not exponentially.

> One thing I'm not too sure of is the portability of macro expansions 
> such as $(TZDIR_$(SET1)) which might make this a non-starter!

Unfortunately you're right, it's not portable, as it doesn't work with 
traditional 'make'.  POSIX isn't clear in this area, but my best guess 
is that POSIX doesn't require support for that sort of usage.  Perhaps 
use a recursive call to $(MAKE) instead?