question on the "::" part of multi-arch builds

[Robert P. J. Day]

  a trivial issue but in the write-up on multi-arch builds, paul uses
the rules:

%.mk:: ;
%:: ${OBJDIR} ; :

although he explains later that the double colons are, strictly
speaking, not necessary, they just speed things up.

  if that's the case (and i'm sure it is), it would be more useful to
show the example with single colons only, and explain the double
colons *later* as a potential improvement.

  when i first read that article, i puzzled over those double colons,
trying desperately to figure out what kind of magic they added to the
recipe, until i read where they weren't technically essential.

  IMHO, for the sake of beginners, the examples should be kept as
simple as possible, and tricky extensions should be added later.  just
my $0.02 canadian (which, these days, is damned near worth $0.02 US.)

rday

p.s.  i'm assuming that the rule for "%.mk" is to handle the inclusion
of "*.mk" files.  if that's the case, then if my top-level makefile is
including, say, Makefile.in, i should add a similar rule for that file
as well, correct?  and any other included files.