missing: don't cater to 'configure.in' in our advice

The use of 'configure.in' as autoconf input now deprecated the development
versions of both Automake and Autoconf, and we'd like to speed up its
demise.

* missing: In the advice displayed in case some autotools are detected to
be missing, refer to 'configure.ac' unconditionally, instead of referring
to 'configure.in' when that file exists in the current directory (and no
'configure.ac' does).

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

diff --git a/lib/missing b/lib/missing
index b24ebab..86301c4 100755 (executable)
--- a/lib/missing
+++ b/lib/missing
@@ -1,7 +1,7 @@
 #! /bin/sh
 # Common wrapper for a few potentially missing GNU programs.
 
-scriptversion=2012-06-23.01; # UTC
+scriptversion=2012-06-25.09; # UTC
 
 # Copyright (C) 1996-2012 Free Software Foundation, Inc.
 # Originally written by Fran,cois Pinard <pinard@iro.umontreal.ca>, 1996.
@@ -29,14 +29,6 @@ if test $# -eq 0; then
   exit 1
 fi
 
-# In the cases where this matters, 'missing' is being run in the
-# srcdir already.
-if test -f configure.ac; then
-  configure_ac=configure.ac
-else
-  configure_ac=configure.in
-fi
-
 case $1 in
 
   --is-lightweight)
@@ -139,10 +131,10 @@ give_advice ()
 
   printf '%s\n' "'$1' is $msg."
  
-  configure_deps="'${configure_ac}' or m4 files included by '${configure_ac}'"
+  configure_deps="'configure.ac' or m4 files included by 'configure.ac'"
   case $normalized_program in
     autoconf*)
-      echo "You should only need it if you modified '${configure_ac}',"
+      echo "You should only need it if you modified 'configure.ac',"
       echo "or m4 files included by it."
       program_details 'autoconf'
       ;;