[gentoo-dev] destdir vs prefix

[jano]

Hi,

i've had this explained to me a few times already, but for some reason,
I'm still having problems grasping the idea.

program is typical autoconf tarball.. ./configure, make, make install.

So when doing the "try make install" command within an .ebuild file,
how do you know whether to use DESTDIR or PREFIX, or both?  I check out
the makefile for this particular program, which has the files depend on
${prefix} (e.g. mandir=${prefix}/man), and a sole line with "DESTDIR =  "

This particular program installs the biaries, docs, etc fine either
way.  If I do:
try make PREFIX=${D} install
however, when reading the /var/db/pkg/blah/CONTENTS file, i see only
those files which I explicitly do a dodoc, dobin, doman, etc.  So an
unmerge/uninstall will not remove the whole program as it should.  I
tried to change it to PREFIX=${D}/usr as I've seen in some ebuilds, no
worky worky.  But when I do:
try make DESTDIR=${D} install
everything shows up the right way, including CONTENTS and stuff.

I'm rendered confused.  Why does it work this way?

jano