install without updating time stamps (was: Autoconf problem.)

[Ralf Wildenhues]

Hello David,

* David Ronis wrote on Mon, Aug 18, 2008 at 03:26:26AM CEST:
> I've just started following evo and friends in svn/trunk.   One thing
> I've noticed is that small changes in one module will trigger almost
> full rebuilds in the remaining ones (e.g., a small change in eds leads
> to most of evo being rebuilt).    I'm doing this within a garnome build
> tree,  and the usual way the build proceeds is to make install in each
> directory (following the correct order of dependencies).

Thank you for the report.  There are two issues:

1) It sounds like the way the build is done could possibly be improved.
(I don't know the software, though, so I'll not look into this further
unless there is interest.)

2) install should be less eager to update time stamps.
For this there is at least one step: recent install-sh from Automake
supports -C which doesn't update the file at all (nor its time stamp)
if the previously installed version didn't change.  This is a bit safer
than GNU install's --preserve-timestamps (you could have manually
changed the previously installed file, after building the new tree;
this would lead to the newly installed file wrongly having an older
time stamp than its prior).

For full nice support of (2), probably a bit more should be done, but I
guess as a workaround you can likely use
  make install INSTALL='$(SHELL) $(top_srcdir)/build-aux/install-sh -C'

with build-aux adjusted to whereever that file is.

Note that the next Automake release will make this operation faster in
many situations (with multi-file install).

Hope that helps.

Cheers,
Ralf