build: require perl 5.6

This reduces the implicit requirement from 5.6.2 back to 5.6,
while raising the explicit requirement to match the actual code.

* configure.ac (PERL): Fail up front if perl is too old.
* NEWS: Document this.
* README: Likewise.
* README-hacking: Likewise.
* lib/Autom4te/ChannelDefs.pm: Bump requirement.
* lib/Autom4te/General.pm: Relax requirement.

6 files changed, 9 insertions, 7 deletions

diff --git a/NEWS b/NEWS
index 74472291..dbc19dc8 100644
--- a/NEWS
+++ b/NEWS
@@ -1,7 +1,9 @@
 GNU Autoconf NEWS - User visible changes.
 
-* Noteworthy changes in release ?.? (????-??-??) [?]
+* Noteworthy changes in release 2.69 (????-??-??) [?]
 
+** Autoconf now requires perl 5.6 or better (but generated configure
+   scripts continue to run without perl).
 
 * Noteworthy changes in release 2.68b (2012-03-01) [beta]
   Released by Eric Blake, based on git versions 2.68.*.
diff --git a/README b/README
index 8e5eb493..6fb53a98 100644
--- a/README
+++ b/README
@@ -12,7 +12,7 @@ macro calls.
 
 Producing configuration scripts using Autoconf requires GNU M4 and
 Perl.  You should install GNU M4 (version 1.4.6 or later is required;
-1.4.14 or later is recommended) and Perl (5.005_03 or later) before
+1.4.14 or later is recommended) and Perl (5.006 or later) before
 configuring Autoconf, so that Autoconf's configure script can find
 them.  The configuration scripts produced by Autoconf are
 self-contained, so their users do not need to have Autoconf (or GNU
diff --git a/README-hacking b/README-hacking
index da57ac43..41d128db 100644
--- a/README-hacking
+++ b/README-hacking
@@ -18,7 +18,7 @@ tools we depend upon, including:
 - Automake 1.10+ <http://www.gnu.org/software/automake/>
 - Help2man 1.29+ <http://www.gnu.org/software/help2man/>
 - M4 1.4.6+ <http://www.gnu.org/software/m4/>
-- Perl 5.005_03+ <http://www.cpan.org/>
+- Perl 5.006+ <http://www.cpan.org/>
 - Texinfo 4.8+ <http://www.gnu.org/software/texinfo/>
 
 The following are useful as well, if you want to be able to run commands
diff --git a/configure.ac b/configure.ac
index 5bf7b9d0..280cc0e5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -135,8 +135,8 @@ AC_SUBST([PERL])dnl
 if test "$PERL" = no; then
   AC_MSG_ERROR([perl is not found])
 fi
-$PERL -e 'require 5.005_03;' || {
-   AC_MSG_ERROR([Perl 5.005_03 or better is required])
+$PERL -e 'require 5.006;' || {
+   AC_MSG_ERROR([Perl 5.006 or better is required])
 }
 
 # Find out whether the system supports flock
diff --git a/lib/Autom4te/ChannelDefs.pm b/lib/Autom4te/ChannelDefs.pm
index 2a1ec4a0..0d5b5c49 100644
--- a/lib/Autom4te/ChannelDefs.pm
+++ b/lib/Autom4te/ChannelDefs.pm
@@ -47,7 +47,7 @@ shorthand function to output on specific channels.
 
 =cut
 
-use 5.005;
+use 5.006;
 use strict;
 use Exporter;
 
diff --git a/lib/Autom4te/General.pm b/lib/Autom4te/General.pm
index 02e3c87f..cc5875d4 100644
--- a/lib/Autom4te/General.pm
+++ b/lib/Autom4te/General.pm
@@ -32,7 +32,7 @@ used in several executables of the Autoconf and Automake packages.
 
 =cut
 
-use 5.006_002;
+use 5.006;
 use Exporter;
 use Autom4te::ChannelDefs;
 use Autom4te::Channels;