Re: PAssing command line arguments for AC_CONFIG_SUBDIR

[John Burger]

Niels Möller writes:

> In lsh I have a toplevel configure script, which uses
> AC_CONFIG_SUBDIRS to run configure in the subdirectories src/nettle
> and src/spki. Both of these subdirectories are libraries, and can be
> distributed and built separately.
>
> The spki library depends on nettle. So when building the spki
> directory separately, it should use configure tests for nettle and use
> the nettle library that is installed on the system. However, when
> building both libraries as parts of lsh, I want to use the included
> nettle library, and ignore any library which is already installed on
> the system.

In this case, a simple thing I've done is to have (my analog of) 
spki/configure look for ../nettle, and use it if it's there.  This is 
obviously less safe than the alternative you suggest:

> One way of doing this is to let spki:s configure script take a command
> line argument --with-nettle=<nettle-directory>, and use that to set up
> -I and -L-flags etc properly.
>
> But then I need lsh:s configure script to add the option on the
> command line when invoking spki's configure script. Can I do that?

You can add args to ac_configure_args - I don't think this is a 
documented part of the Autoconf interface, but I've done this as well.  
This will pass the extra args to all of the sub-configures, which isn't 
usually a problem, but might be.

Or you could just have your main configure script call the subsidiary 
one directly, with whatever args you want.  Unfortunately, doing this 
right also involves the undocumented ac_configure_args, if you want to 
pass on everything from the original invocation.

- John Burger
  MITRE