incomplete warning message

[Bruno Haible]

Hi,

Here's a case of an incomplete invocation stack trace in an autoconf warning:

  $ autoconf
  configure.ac:63: warning: gl_LIBUNISTRING_LIBSOURCE was called before 
gl_LIBUNISTRING
  m4/libunistring-base.m4:21: gl_LIBUNISTRING_LIBSOURCE is expanded from...
  m4/gnulib-comp.m4:148: gl_INIT is expanded from...
  configure.ac:63: the top level
  configure.ac:63: warning: gl_LIBUNISTRING_LIBHEADER was called before 
gl_LIBUNISTRING
  m4/libunistring-base.m4:53: gl_LIBUNISTRING_LIBHEADER is expanded from...

The last line looks like the stack trace would include at least one more line.
But it ends abruptly.

This is with autoconf-2.65, but can be reproduced with versions 2.61..2.64 as 
well.

How to reproduce:
  $ wget http://www.haible.de/bruno/gnu/autoconf-bug-20100531.tar.gz
  $ tar xvfz autoconf-bug-20100531.tar.gz
  $ cd autoconf-bug-20100531
  $ autoconf

Bruno