Re: [PATCH 1/2] AC_CONFIG_MACRO_DIR: accept more than one argument

[Eric Blake]

On 07/04/2012 05:03 AM, Eric Blake wrote:

> Would it also make sense to allow multiple calls to AC_CONFIG_MACRO_DIR
> to stack, as in:
> 
> AC_CONFIG_MACRO_DIR([dir1])
> AC_CONFIG_MACRO_DIR([dir2])
> 
> And should we mention that the first directory listed has special
> significance to other tools like libtool that use the first directory
> (and ignore subsequent directories) when first preparing a package with
> libtoolize?  For that matter, I'd have to investigate whether libtoolize
> uses grep or autoconf tracing;

Libtool 2.4.2 (the current release) uses grep tracing; but libtool
commit 2a71b02b has already converted over to m4 tracing.  I'm not sure
if the m4 tracing will gracefully handle whitespace-separated
directories or multiple invocations, but the old code:

-   /AC_CONFIG_MACRO_DIR(/ {
-       s,^.*AC_CONFIG_MACRO_DIR([[  ]*\([^])]*\).*$,ac_macro_dir=\1,
-       p
-        }

definitely does NOT handle whitespace lists, and with multiple calls,
appears to reassign $ac_macro_dir to the last call rather than the first
(yuck).

I think we're stuck for compatibility with providing a new macro for
listing subsidiary directories, and that users that plan to interact
with old libtool must use something like:

AC_CONFIG_MACRO_DIR([dir1])
AC_CONFIG_MACRO_DIRS([dir2 dir3])
AC_CONFIG_MACRO_DIRS([dir4])

where the new macro can stack or take whitespace lists.  The new macro
can also auto-call AC_CONFIG_MACRO_DIR() for its first argument for new
libtool that traces rather than using sed, but if you are porting to
older libtool, explicitly spelling out the old name is important.

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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