Patch to support $DESTDIR based installs.

[Dévai Tamás]

On Fri, 02 Apr 2010 14:30:28 +0200, Mads Kiilerich wrote:
> Please tell us why you and everybody else wants this.
> 
> (Patches and discussion of them is more appropriate on mercurial-devel.)
> 
> /Mads
> 

Hi,

installing software (including, but not limited to Mercurial) not to the
live system, but another place (what packagers usually do) can be
accomplished via two ways:

1) setting PREFIX (or the equivalent Makefile variable) to the full
installation path, e.g. PREFIX=/var/pkg/install/usr. This approach might
cause troubles with symlinks. (Yes, I know that currently Mercurial
doesn't install any symlinks.)

2) using the de facto standard DESTDIR variable, e.g.
DESTDIR=/var/pkg/install PREFIX=/usr.

You must understand, that in the case of Mercurial it doesn't matter,
whether I choose (1) or (2) from above. There is an inconsistency in the
Makefiles, the one in doc/ does support DESTDIR, the main one doesn't.
Therefore I thought it would be best to unify them (in this regard), so
that either both support DESTDIR or both doesn't.

Regards,
Dévai Tamás