libqof variables in configure.in (Fwd: gentoo ebuild)

[Christian Stimming]

Hi,

Derek Atkins schrieb:
>>>3. In *addition* to the "make DISTDIR..." solution I would like to
>>>enable Martin's/gentoo's original approach "make prefix=/my/sandbox
>>>install" as well. 
>>
>>>Proposed patch:
>>> >         QOF_VERSION="internal"
>>> >         QOF_PREFIX="internal"
>>> > -       QOF_XML_DIR=`eval echo ${datadir}/xml/qsf`
>>> > +       QOF_XML_DIR="\${datadir}/xml/qsf"
>>
>>OK, I'll test with OSX and go from there.
> 
> I'm concerned that:
> 
>   make install prefix=/tmp/dir/usr
> 
> .. will cause the program to rewrite the configuration file to look in
> /tmp/dir/usr/bin when really /tmp/dir is just a temporary location for
> the package management system to put the files until it can get
> packaged and then installed into /usr/bin..

This concern is totally valid. In the case in question, however, the 
changed $prefix at installation time does not change the value in the C 
code, because the rule for qsf-dir.h depends only on qsf-dir.h.in (and 
is implicitly invoked via BUILT_SOURCES and CONFIG_CLEAN_FILES -- by the 
way, is CONFIG_CLEAN_FILES actually being used anywhere? The automake 
and autoconf manuals don't mention that variable).

In other words, the rule for qsf-dir.h triggers at "make all" and it 
will definitely not trigger again on "make install". So the proposed 
patch is not affected by that concern. In general this concern stays 
perfectly valid and should be checked for always.

> The real question is:  why is the 'user' installing using 'prefix='
> instead of DESTDIR?  

I haven't heard of it before, too, but from what Martin Klaffenboeck 
said it seems to be a common usage in gentoo. The GNU coding standards
http://www.gnu.org/prep/standards/html_node/Directory-Variables.html
don't say anything specific about the interplay of automake and make 
here; they only recommend

   "Running ‘make install’ with a different value of prefix from the one 
used to build the program should not recompile the program. "

To me this sounds as if gentoo's approach in principle is valid from the 
Makefile point of view. So if it is possible for us to support that 
behaviour without breaking anything existing then I don't see any reason 
not to do so.

 > Not that it matters to us, but we should
 > make sure that we don't re-write anything during 'make install'

Of course. This needs to be ensured regardless of how the variables are 
set, so that is a requirement independent of the currently discussed change.

Christian