texinfo: warn about future use of '--tidy'

Starting from the next major release of Automake (likely 1.13) we
want to start passing the '--tidy' option to texi2dvi and texi2pdf
invocations, so that auxiliary TeX-generated files can be kept
around (thus speeding up rebuilding of DVI and PDF output) without
cluttering the build directory too much.

Since the '--tidy' option was introduced in Texinfo 4.9 (as
documented in the Texinfo distribution's NEWS file), this also
means that Makefiles generated by future Automake versions will
require at least that version of Texinfo (at the time of writing
four years and nine months old).

The users should be warned about the planned behavioral change
and the new version requirement it will entail.

See also automake bug#11146.

* NEWS (Planned Backward Incompatibilities): Add entry about use
of the '--tidy' option and requirement of Texinfo 4.9.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 3e54207c7..3c0df1b8f 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,12 @@ New in 1.11a:
 
 * WARNING: Future backward-incompatibilities!
 
+  - Starting from the next major Automake version (1.13), the rules to
+    build pdf, ps and dvi output from Texinfo input will use the '--tidy'
+    option by default.  Since such an option was introduced in Texinfo
+    4.9, this means that Makefiles generated by future Automake versions
+    will require at least that version of Texinfo.
+
   - Starting from the next major Automake version (1.13), the parallel
     testsuite harness (previously only enabled by the 'parallel-tests'
     option) will become the default one; the older serial testsuite