Deterministic "ar" breaks build

[Ole Streicher <olebole@debian.org>]

Hi,

since a while, the "ar" command is built with --enable-deterministic-archives,
which basiacally resets (among others) the timestamp to null. This has
the unfortune disadvantage, that Makefiles that use this timestamp do
not work correctly anymore. For example, my wcslib package has

$(WCSLIB)(%.o) : %.c
	-@ echo ''
	   $(CC) $(CPPFLAGS) $(CFLAGS) -c $<
	   $(AR) Ur $(WCSLIB) $%
	-@ $(RM) $%

which results in a repeated compilation of all files every time when a
dependency of the wcslib appears.

I could use the "U" flag or ar, but is there a way to get around this
*and* keep determinism at the same time? I don't want to rewrite the
whole Makefile logic here, however.

Best regards

Ole