RFC: Top level configure: Require a minimum version 6.8 texinfo

[Nick Clifton <nickc@redhat.com>]

Hi Guys,

  Currently the top level configure.ac file sets the minimum required
  version of texinfo to be 4.7.  I would like to propose changing this
  to 6.8.
  
  The reason for the change is that the bfd documentation now needs at
  least version 6.8 in order to build[1][2].  Given that 4.7 is now
  almost 20 years old (it was released in April 2004), updating the
  requirement to a newer version does seem reasonable.  On the other
  hand 6.8 is quite new (it was released in March 2021), so a lot of
  systems out there may not have it.

  Thoughts ?

Cheers
  Nick

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=30703
[2] https://sourceware.org/pipermail/binutils/2023-February/125943.html

Suggested patch:

diff --git a/configure.ac b/configure.ac
index 01cfd017273..10bfef1c6c5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3678,10 +3678,10 @@ case " $build_configdirs " in
   *" texinfo "*) MAKEINFO='$$r/$(BUILD_SUBDIR)/texinfo/makeinfo/makeinfo' ;;
   *)
 changequote(,)
-    # For an installed makeinfo, we require it to be from texinfo 4.7 or
+    # For an installed makeinfo, we require it to be from texinfo 6.8 or
     # higher, else we use the "missing" dummy.
     if ${MAKEINFO} --version \
-       | egrep 'texinfo[^0-9]*(4\.([7-9]|[1-9][0-9])|[5-9]|[1-9][0-9])' >/dev/null 2>&1; then
+       | egrep 'texinfo[^0-9]*(6\.([8-9]|[1-9][0-9])|[7-9]|[1-9][0-9])' >/dev/null 2>&1; then
       :
     else
       MAKEINFO="$MISSING makeinfo"