[Zlib-devel] zlib-1.2.3-cos2

[Greg Roelofs]

> > > I applied Enrico Weigelt's patches, including the pkgconfig patch,
> > > but excluding the destdir patch and the treebuild patch. I find
> > > destdir pointless (why not just run "make prefix=/my/prefix" as it
> > > is customary with other software?)

> > Because $prefix is just the prefix of several directories (ie.
> > $libdir) within the system tree, where $DESTDIR specifies where the
> > system root is while the installation procedure. $prefix is also
> > relevant for runtime, where $DESTDIR is not.

> I'm not sure I understand. The way I see it, you're introducing an extra
> symbol without solving any problem. (Is there any problem, at all?)
> Why not just do "make install prefix=/my/prefix libdir=/my/libdir"?

Here's the deal:  DESTDIR is solely for that--where the tree gets dumped
on _this_ build.  prefix is for the final, intended install location AND
for internal paths(!!!).  prefix often ends up both in generated makefiles
and inside binaries.  DESTDIR never does.  They are not the same thing,
and you cannot, in general, combine both of them into one variable.

DESTDIR is also very useful for distributors (and zlib maintainers) who
need to test, without wiping out their own installations, that prefix is
doing what it's supposed to be doing.  But that's a secondary purpose.

Greg

P.S.  If that still doesn't make sense to you, visualize cross-compilation
      and NFS root...