[gimp] configure: add an info message to advise building with meson and report bugs.

[Jehan <jehanp src gnome org>]

commit bfc9e4bb72391c740574ae20a138cdea704335af
Author: Jehan <jehan girinstud io>
Date:   Tue Oct 11 16:38:18 2022 +0200

    configure: add an info message to advise building with meson and report bugs.

 configure.ac | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/configure.ac b/configure.ac
index 713feb0b0b..231f6a173d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3284,7 +3284,12 @@ if test "x$required_deps" = "x"; then
   AC_MSG_RESULT([
 Building GIMP with prefix=$prefix, datarootdir=$datarootdir
 Desktop files install into $DESKTOP_DATADIR
-$optional_deps]);
+$optional_deps
+
+INFO: MESON BUILD IS IN EXTENSIVE TESTING PHASE TO LIKELY REPLACE AUTOTOOLS!
+
+      we now encourage usage of meson for packagers, instead of autotools.
+      Please build GIMP with meson and report bugs.]);
 else
   AC_MSG_ERROR([
 $optional_deps