missing --run/not run

[Norman Gray]

Greetings,

We as a project have decided to go the route of checking 
autotool-generated files into our CVS repository, and as a result are 
discovering the full subtleties of the consequences of that, in 
particular the issues concerning timestamps in checked-out files.  I 
think I've addressed this problem adequately (and I'm asking for advice 
on that), but it might be that automake can fairly straightforwardly 
help make this easier.

The problem is, of course, the `missing' script, and what happens when 
a checked-out generated file apparently needs to be rebuilt on a 
developer's machine.  The `missing --run' mechanism works fine when the 
locally-installed autoconf is sufficiently up-to-date to work, and also 
when there is _no_ autoconf installed, however it can fail if there 
_is_ a local autoconf, but it is too old to process the 
configure.{in,ac} file correctly.

One of the solutions mentioned in the automake manual is to use a 
script to simply update the timestamps of generated files, and mentions 
that the GCC folk do this.  I've looked at this script, and while it 
surely works for them, it's not generic, and it's fragile.  However, 
this is essentially what the `missing' script does when it's invoked 
without the --run option, which means that the problem turns into that 
of how to suppress that option in the specific case when you know you 
simply need to update timestamps.  There seems to be two routes:

First is to write a wrapper for `make' which edits the Makefile with 
"sed 's/missing *--run/missing /", then invokes make on that makefile.  
This works for me, as far as I've been able to test it (always tricky 
in these situations).

The second route is to have the Makefile include lines like

    missing_run=--run
    ...
    AUTOCONF = ${SHELL} /blah/blah/missing $(missing_run) autoconf

That works as usual when invoked as usual, but the command

    make missing_run=

is effectively the update-the-timestamps script, and perfectly generic. 
 Since it never actually attempts to run 
autoconf/automake/autoheader/etc, it is completely independent of the 
versions which are or are not installed on the local machine.  This 
also works for me (with hand-hacking of the Makefile, admittedly, 
rather than hacking local m4 macros)

So, questions:

Is this in fact a useful thing to do, or have I missed some obvious 
showstopping problem?

If the second route is in fact useful, is this something it might be 
handy to include in the Makefile that automake/autoconf generates?  Or 
is this really an autoconf question, and not an automake one? -- I'm a 
little confused.

All the best,

Norman


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Norman Gray                   http://www.astro.gla.ac.uk/users/norman/
Physics and Astronomy, University of Glasgow    address@hidden